diff --git a/.eslintrc b/.eslintrc
index e1337ccf95..096f7c8ab0 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -2,7 +2,11 @@
   "extends": ["webpack", "prettier"],
   "globals": {
     "document": true,
-    "window": true
+    "window": true,
+    "self": true,
+    "WorkerGlobalScope": true,
+    "__resourceQuery": true,
+    "__webpack_dev_server_client__": true
   },
   "parserOptions": {
     "sourceType": "script"
diff --git a/azure-pipelines.yml b/azure-pipelines.yml
index 8977de369e..d0fdf318cd 100644
--- a/azure-pipelines.yml
+++ b/azure-pipelines.yml
@@ -47,9 +47,6 @@ jobs:
         node-8:
           node_version: ^8.9.0
           webpack_version: latest
-        node-6:
-          node_version: ^6.9.0
-          webpack_version: latest
     steps:
       - task: NodeTool@0
         inputs:
@@ -98,9 +95,6 @@ jobs:
         node-8:
           node_version: ^8.9.0
           webpack_version: latest
-        node-6:
-          node_version: ^6.9.0
-          webpack_version: latest
     steps:
       - task: NodeTool@0
         inputs:
@@ -149,9 +143,6 @@ jobs:
         node-8:
           node_version: ^8.9.0
           webpack_version: latest
-        node-6:
-          node_version: ^6.9.0
-          webpack_version: latest
     steps:
       - script: 'git config --global core.autocrlf input'
         displayName: 'Config git core.autocrlf'
diff --git a/client-src/.eslintrc b/client-src/.eslintrc
new file mode 100644
index 0000000000..bd14a19ef2
--- /dev/null
+++ b/client-src/.eslintrc
@@ -0,0 +1,5 @@
+{
+  "parserOptions": {
+    "sourceType": "module"
+  }
+}
diff --git a/client-src/clients/BaseClient.js b/client-src/clients/BaseClient.js
index 1dfa65911b..7c47b70e2a 100644
--- a/client-src/clients/BaseClient.js
+++ b/client-src/clients/BaseClient.js
@@ -1,5 +1,3 @@
-'use strict';
-
 /* eslint-disable
   no-unused-vars
 */
diff --git a/client-src/clients/SockJSClient.js b/client-src/clients/SockJSClient.js
index 388c25fef1..5824bc9af9 100644
--- a/client-src/clients/SockJSClient.js
+++ b/client-src/clients/SockJSClient.js
@@ -1,5 +1,3 @@
-'use strict';
-
 /* eslint-disable
   no-unused-vars
 */
diff --git a/client-src/clients/WebsocketClient.js b/client-src/clients/WebsocketClient.js
index 1ae8ecf2fb..6b4e5acf91 100644
--- a/client-src/clients/WebsocketClient.js
+++ b/client-src/clients/WebsocketClient.js
@@ -1,5 +1,3 @@
-'use strict';
-
 const BaseClient = require('./BaseClient');
 
 module.exports = class WebsocketClient extends BaseClient {};
diff --git a/client-src/default/index.js b/client-src/default/index.js
index dede6f0763..df7432b5ea 100644
--- a/client-src/default/index.js
+++ b/client-src/default/index.js
@@ -1,14 +1,14 @@
-'use strict';
-
-/* global __resourceQuery WorkerGlobalScope self */
 /* eslint prefer-destructuring: off */
-const stripAnsi = require('strip-ansi');
-const socket = require('./socket');
-const overlay = require('./overlay');
-const { log, setLogLevel } = require('./utils/log');
-const sendMessage = require('./utils/sendMessage');
-const reloadApp = require('./utils/reloadApp');
-const createSocketUrl = require('./utils/createSocketUrl');
+import stripAnsi from 'strip-ansi';
+import socket from './socket';
+import {
+  clear as clearOverlay,
+  showMessage as showMessageOverlay,
+} from './overlay';
+import { log, setLogLevel } from './utils/log';
+import sendMessage from './utils/sendMessage';
+import reloadApp from './utils/reloadApp';
+import createSocketUrl from './utils/createSocketUrl';
 
 const status = {
   isUnloading: false,
@@ -47,7 +47,7 @@ const onSocketMessage = {
     log.info('[WDS] App updated. Recompiling...');
     // fixes #1042. overlay doesn't clear if errors are fixed but warnings remain.
     if (options.useWarningOverlay || options.useErrorOverlay) {
-      overlay.clear();
+      clearOverlay();
     }
     sendMessage('Invalid');
   },
@@ -57,7 +57,7 @@ const onSocketMessage = {
   'still-ok': function stillOk() {
     log.info('[WDS] Nothing changed.');
     if (options.useWarningOverlay || options.useErrorOverlay) {
-      overlay.clear();
+      clearOverlay();
     }
     sendMessage('StillOk');
   },
@@ -93,7 +93,7 @@ const onSocketMessage = {
   ok() {
     sendMessage('Ok');
     if (options.useWarningOverlay || options.useErrorOverlay) {
-      overlay.clear();
+      clearOverlay();
     }
     if (options.initial) {
       return (options.initial = false);
@@ -112,7 +112,7 @@ const onSocketMessage = {
       log.warn(strippedWarnings[i]);
     }
     if (options.useWarningOverlay) {
-      overlay.showMessage(warnings);
+      showMessageOverlay(warnings);
     }
 
     if (options.initial) {
@@ -128,7 +128,7 @@ const onSocketMessage = {
       log.error(strippedErrors[i]);
     }
     if (options.useErrorOverlay) {
-      overlay.showMessage(errors);
+      showMessageOverlay(errors);
     }
     options.initial = false;
   },
diff --git a/client-src/default/overlay.js b/client-src/default/overlay.js
index a1bb6cef2b..39963a246b 100644
--- a/client-src/default/overlay.js
+++ b/client-src/default/overlay.js
@@ -1,12 +1,10 @@
-'use strict';
-
 // The error overlay is inspired (and mostly copied) from Create React App (https://github.com/facebookincubator/create-react-app)
 // They, in turn, got inspired by webpack-hot-middleware (https://github.com/glenjamin/webpack-hot-middleware).
 
-const ansiHTML = require('ansi-html');
-const { AllHtmlEntities } = require('html-entities');
+import ansiHTML from 'ansi-html';
+import { AllHtmlEntities as Entities } from 'html-entities';
 
-const entities = new AllHtmlEntities();
+const entities = new Entities();
 const colors = {
   reset: ['transparent', 'transparent'],
   black: '181818',
@@ -96,7 +94,7 @@ function ensureOverlayDivExists(onOverlayDivReady) {
 }
 
 // Successful compilation.
-function clear() {
+export function clear() {
   if (!overlayDiv) {
     // It is not there in the first place.
     return;
@@ -110,7 +108,7 @@ function clear() {
 }
 
 // Compilation with errors (e.g. syntax error or missing modules).
-function showMessage(messages) {
+export function showMessage(messages) {
   ensureOverlayDivExists((div) => {
     // Make it look similar to our terminal.
     div.innerHTML = `<span style="color: #${
@@ -120,8 +118,3 @@ function showMessage(messages) {
     )}`;
   });
 }
-
-module.exports = {
-  clear,
-  showMessage,
-};
diff --git a/client-src/default/socket.js b/client-src/default/socket.js
index 7752ffea8a..382fe80fdc 100644
--- a/client-src/default/socket.js
+++ b/client-src/default/socket.js
@@ -1,6 +1,3 @@
-'use strict';
-
-/* global __webpack_dev_server_client__ */
 /* eslint-disable
   camelcase
 */
@@ -58,4 +55,4 @@ const socket = function initSocket(url, handlers) {
   });
 };
 
-module.exports = socket;
+export default socket;
diff --git a/client-src/default/utils/createSocketUrl.js b/client-src/default/utils/createSocketUrl.js
index 98d0f13914..fb78fee60b 100644
--- a/client-src/default/utils/createSocketUrl.js
+++ b/client-src/default/utils/createSocketUrl.js
@@ -1,10 +1,6 @@
-'use strict';
-
-/* global self */
-
-const url = require('url');
-const querystring = require('querystring');
-const getCurrentScriptSource = require('./getCurrentScriptSource');
+import url from 'url';
+import querystring from 'querystring';
+import getCurrentScriptSource from './getCurrentScriptSource';
 
 function createSocketUrl(resourceQuery) {
   let urlParts;
@@ -80,4 +76,4 @@ function createSocketUrl(resourceQuery) {
   });
 }
 
-module.exports = createSocketUrl;
+export default createSocketUrl;
diff --git a/client-src/default/utils/getCurrentScriptSource.js b/client-src/default/utils/getCurrentScriptSource.js
index 7d1d609a6a..8a4244a2ee 100644
--- a/client-src/default/utils/getCurrentScriptSource.js
+++ b/client-src/default/utils/getCurrentScriptSource.js
@@ -1,5 +1,3 @@
-'use strict';
-
 function getCurrentScriptSource() {
   // `document.currentScript` is the most accurate way to find the current script,
   // but is not supported in all browsers.
@@ -17,4 +15,4 @@ function getCurrentScriptSource() {
   throw new Error('[WDS] Failed to get current script source.');
 }
 
-module.exports = getCurrentScriptSource;
+export default getCurrentScriptSource;
diff --git a/client-src/default/utils/log.js b/client-src/default/utils/log.js
index 91d9aa763b..db9301cad1 100644
--- a/client-src/default/utils/log.js
+++ b/client-src/default/utils/log.js
@@ -1,6 +1,6 @@
-'use strict';
+import { getLogger } from 'loglevel';
 
-const log = require('loglevel').getLogger('webpack-dev-server');
+export const log = getLogger('webpack-dev-server');
 
 const INFO = 'info';
 const WARN = 'warn';
@@ -8,16 +8,11 @@ const ERROR = 'error';
 const DEBUG = 'debug';
 const TRACE = 'trace';
 const SILENT = 'silent';
-// deprecated
-// TODO: remove these at major released
-// https://github.com/webpack/webpack-dev-server/pull/1825
-const WARNING = 'warning';
-const NONE = 'none';
 
 // Set the default log level
 log.setDefaultLevel(INFO);
 
-function setLogLevel(level) {
+export function setLogLevel(level) {
   switch (level) {
     case INFO:
     case WARN:
@@ -26,13 +21,6 @@ function setLogLevel(level) {
     case TRACE:
       log.setLevel(level);
       break;
-    // deprecated
-    case WARNING:
-      // loglevel's warning name is different from webpack's
-      log.setLevel('warn');
-      break;
-    // deprecated
-    case NONE:
     case SILENT:
       log.disableAll();
       break;
@@ -40,8 +28,3 @@ function setLogLevel(level) {
       log.error(`[WDS] Unknown clientLogLevel '${level}'`);
   }
 }
-
-module.exports = {
-  log,
-  setLogLevel,
-};
diff --git a/client-src/default/utils/reloadApp.js b/client-src/default/utils/reloadApp.js
index 7237ef6b25..d402f2e1f2 100644
--- a/client-src/default/utils/reloadApp.js
+++ b/client-src/default/utils/reloadApp.js
@@ -1,8 +1,4 @@
-'use strict';
-
-/* global WorkerGlobalScope self */
-
-const { log } = require('./log');
+import { log } from './log';
 
 function reloadApp(
   { hotReload, hot, liveReload },
@@ -46,4 +42,4 @@ function reloadApp(
   }
 }
 
-module.exports = reloadApp;
+export default reloadApp;
diff --git a/client-src/default/utils/sendMessage.js b/client-src/default/utils/sendMessage.js
index f4dc2555dc..6cf28a5dd1 100644
--- a/client-src/default/utils/sendMessage.js
+++ b/client-src/default/utils/sendMessage.js
@@ -1,9 +1,5 @@
-'use strict';
-
-/* global __resourceQuery WorkerGlobalScope self */
-
 // Send messages to the outside, so plugins can consume it.
-function sendMsg(type, data) {
+function sendMessage(type, data) {
   if (
     typeof self !== 'undefined' &&
     (typeof WorkerGlobalScope === 'undefined' ||
@@ -19,4 +15,4 @@ function sendMsg(type, data) {
   }
 }
 
-module.exports = sendMsg;
+export default sendMessage;
diff --git a/client-src/default/webpack.config.js b/client-src/default/webpack.config.js
index ac001f26d7..ed679ca93c 100644
--- a/client-src/default/webpack.config.js
+++ b/client-src/default/webpack.config.js
@@ -1,5 +1,3 @@
-'use strict';
-
 const webpack = require('webpack');
 
 module.exports = {
diff --git a/client-src/live/index.js b/client-src/live/index.js
index dd5feef14b..77fc300311 100644
--- a/client-src/live/index.js
+++ b/client-src/live/index.js
@@ -1,11 +1,9 @@
-'use strict';
-
 /* eslint import/no-extraneous-dependencies: off, global-require: off */
 
-const $ = require('jquery');
-const stripAnsi = require('strip-ansi');
-const socket = require('../default/socket');
-require('./style.css');
+import $ from 'jquery';
+import stripAnsi from 'strip-ansi';
+import socket from '../default/socket';
+import './style.css';
 
 let hot = false;
 let currentHash = '';
diff --git a/client-src/live/webpack.config.js b/client-src/live/webpack.config.js
index 3887b38b2b..2815e20683 100644
--- a/client-src/live/webpack.config.js
+++ b/client-src/live/webpack.config.js
@@ -1,5 +1,3 @@
-'use strict';
-
 const path = require('path');
 const webpack = require('webpack');
 const CopyPlugin = require('copy-webpack-plugin');
diff --git a/client-src/sockjs/index.js b/client-src/sockjs/index.js
index a7db01b9d3..988f4885e3 100644
--- a/client-src/sockjs/index.js
+++ b/client-src/sockjs/index.js
@@ -1,3 +1,3 @@
-'use strict';
+import client from 'sockjs-client';
 
-module.exports = require('sockjs-client');
+export default client;
diff --git a/client-src/sockjs/webpack.config.js b/client-src/sockjs/webpack.config.js
index 4847a2b910..61c7f655bc 100644
--- a/client-src/sockjs/webpack.config.js
+++ b/client-src/sockjs/webpack.config.js
@@ -1,5 +1,3 @@
-'use strict';
-
 module.exports = {
   mode: 'production',
   output: {
diff --git a/globalSetupTest.js b/globalSetupTest.js
index c82cbb1432..1e4123b5fa 100644
--- a/globalSetupTest.js
+++ b/globalSetupTest.js
@@ -7,8 +7,7 @@ const ports = require('./test/ports-map');
 async function validatePorts() {
   const samples = [];
 
-  Object.keys(ports).forEach((key) => {
-    const value = ports[key];
+  Object.entries(ports).forEach(([key, value]) => {
     const arr = Array.isArray(value) ? value : [value];
 
     arr.forEach((port) => {
diff --git a/lib/options.json b/lib/options.json
index 349973498b..5a1a3e2df3 100644
--- a/lib/options.json
+++ b/lib/options.json
@@ -37,16 +37,7 @@
       ]
     },
     "clientLogLevel": {
-      "enum": [
-        "info",
-        "warn",
-        "error",
-        "debug",
-        "trace",
-        "silent",
-        "none",
-        "warning"
-      ]
+      "enum": ["info", "warn", "error", "debug", "trace", "silent"]
     },
     "compress": {
       "type": "boolean"
@@ -389,7 +380,7 @@
       "bonjour": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserverbonjour)",
       "ca": "should be {String|Buffer}",
       "cert": "should be {String|Buffer}",
-      "clientLogLevel": "should be {String} and equal to one of the allowed values\n\n [ 'none', 'silent', 'info', 'debug', 'trace', 'error', 'warning', 'warn' ]\n\n (https://webpack.js.org/configuration/dev-server/#devserverclientloglevel)",
+      "clientLogLevel": "should be {String} and equal to one of the allowed values\n\n [ 'silent', 'info', 'debug', 'trace', 'error', 'warn' ]\n\n (https://webpack.js.org/configuration/dev-server/#devserverclientloglevel)",
       "compress": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devservercompress)",
       "contentBase": "should be {Number|String|Array} (https://webpack.js.org/configuration/dev-server/#devservercontentbase)",
       "disableHostCheck": "should be {Boolean} (https://webpack.js.org/configuration/dev-server/#devserverdisablehostcheck)",
diff --git a/lib/utils/runOpen.js b/lib/utils/runOpen.js
index a2757ab919..7f0b814ffe 100644
--- a/lib/utils/runOpen.js
+++ b/lib/utils/runOpen.js
@@ -1,6 +1,6 @@
 'use strict';
 
-const open = require('opn');
+const open = require('open');
 const isAbsoluteUrl = require('is-absolute-url');
 
 function runOpen(uri, options, log) {
diff --git a/package-lock.json b/package-lock.json
index 5183310c2d..408669325e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -20,6 +20,58 @@
         "output-file-sync": "^2.0.0",
         "slash": "^2.0.0",
         "source-map": "^0.5.0"
+      },
+      "dependencies": {
+        "binary-extensions": {
+          "version": "1.13.1",
+          "resolved": "https://registry.npmjs.org/binary-extensions/-/binary-extensions-1.13.1.tgz",
+          "integrity": "sha512-Un7MIEDdUC5gNpcGDV97op1Ywk748MpHcFTHoYs6qnj1Z3j7I53VG3nwZhKzoBZmbdRNnb6WRdFlwl7tSDuZGw==",
+          "dev": true,
+          "optional": true
+        },
+        "chokidar": {
+          "version": "2.1.6",
+          "resolved": "https://registry.npmjs.org/chokidar/-/chokidar-2.1.6.tgz",
+          "integrity": "sha512-V2jUo67OKkc6ySiRpJrjlpJKl9kDuG+Xb8VgsGzb+aEouhgS1D0weyPU4lEzdAcsCAvrih2J2BqyXqHWvVLw5g==",
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "anymatch": "^2.0.0",
+            "async-each": "^1.0.1",
+            "braces": "^2.3.2",
+            "fsevents": "^1.2.7",
+            "glob-parent": "^3.1.0",
+            "inherits": "^2.0.3",
+            "is-binary-path": "^1.0.0",
+            "is-glob": "^4.0.0",
+            "normalize-path": "^3.0.0",
+            "path-is-absolute": "^1.0.0",
+            "readdirp": "^2.2.1",
+            "upath": "^1.1.1"
+          }
+        },
+        "is-binary-path": {
+          "version": "1.0.1",
+          "resolved": "https://registry.npmjs.org/is-binary-path/-/is-binary-path-1.0.1.tgz",
+          "integrity": "sha1-dfFmQrSA8YenEcgUFh/TpKdlWJg=",
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "binary-extensions": "^1.0.0"
+          }
+        },
+        "readdirp": {
+          "version": "2.2.1",
+          "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-2.2.1.tgz",
+          "integrity": "sha512-1JU/8q+VgFZyxwrJ+SVIOsh+KywWGpds3NTqikiKpDMZWScmAYyKIgqkO+ARvNWJfXeXR1zxz7aHF4u4CyH6vQ==",
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "graceful-fs": "^4.1.11",
+            "micromatch": "^3.1.10",
+            "readable-stream": "^2.0.2"
+          }
+        }
       }
     },
     "@babel/code-frame": {
@@ -1340,6 +1392,29 @@
         "rimraf": "^2.5.2"
       }
     },
+    "@nodelib/fs.scandir": {
+      "version": "2.1.1",
+      "resolved": "https://registry.npmjs.org/@nodelib/fs.scandir/-/fs.scandir-2.1.1.tgz",
+      "integrity": "sha512-NT/skIZjgotDSiXs0WqYhgcuBKhUMgfekCmCGtkUAiLqZdOnrdjmZr9wRl3ll64J9NF79uZ4fk16Dx0yMc/Xbg==",
+      "requires": {
+        "@nodelib/fs.stat": "2.0.1",
+        "run-parallel": "^1.1.9"
+      }
+    },
+    "@nodelib/fs.stat": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/@nodelib/fs.stat/-/fs.stat-2.0.1.tgz",
+      "integrity": "sha512-+RqhBlLn6YRBGOIoVYthsG0J9dfpO79eJyN7BYBkZJtfqrBwf2KK+rD/M/yjZR6WBmIhAgOV7S60eCgaSWtbFw=="
+    },
+    "@nodelib/fs.walk": {
+      "version": "1.2.2",
+      "resolved": "https://registry.npmjs.org/@nodelib/fs.walk/-/fs.walk-1.2.2.tgz",
+      "integrity": "sha512-J/DR3+W12uCzAJkw7niXDcqcKBg6+5G5Q/ZpThpGNzAUz70eOR6RV4XnnSN01qHZiVl0eavoxJsBypQoKsV2QQ==",
+      "requires": {
+        "@nodelib/fs.scandir": "2.1.1",
+        "fastq": "^1.6.0"
+      }
+    },
     "@samverschueren/stream-to-observable": {
       "version": "0.3.0",
       "resolved": "https://registry.npmjs.org/@samverschueren/stream-to-observable/-/stream-to-observable-0.3.0.tgz",
@@ -1436,9 +1511,9 @@
       "integrity": "sha512-tHq6qdbT9U1IRSGf14CL0pUlULksvY9OZ+5eEgl1N7t+OA3tGvNpxJCzuKQlsNgCVwbAs670L1vcVQi8j9HjnA=="
     },
     "@types/node": {
-      "version": "12.0.2",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-12.0.2.tgz",
-      "integrity": "sha512-5tabW/i+9mhrfEOUcLDu2xBPsHJ+X5Orqy9FKpale3SjDA17j5AEpYq5vfy3oAeAHGcvANRCO3NV3d2D6q3NiA=="
+      "version": "12.0.10",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-12.0.10.tgz",
+      "integrity": "sha512-LcsGbPomWsad6wmMNv7nBLw7YYYyfdYcz6xryKYQhx89c3XXan+8Q6AJ43G5XDIaklaVkK3mE4fCb0SBvMiPSQ=="
     },
     "@types/normalize-package-data": {
       "version": "2.4.0",
@@ -1446,6 +1521,11 @@
       "integrity": "sha512-f5j5b/Gf71L+dbqxIpQ4Z2WlmI/mPJ0fOkGGmFgtb6sAu97EPczzbS3/tJKxmcYDj55OX6ssqwDAWOHIYDRDGA==",
       "dev": true
     },
+    "@types/retry": {
+      "version": "0.12.0",
+      "resolved": "https://registry.npmjs.org/@types/retry/-/retry-0.12.0.tgz",
+      "integrity": "sha512-wWKOClTTiizcZhXnPY4wikVAwmdYHp8q6DmC+EJUzAMsycb7HB32Kh9RN4+0gExjmPmZSAQjgURXIGATPegAvA=="
+    },
     "@types/stack-utils": {
       "version": "1.0.1",
       "resolved": "https://registry.npmjs.org/@types/stack-utils/-/stack-utils-1.0.1.tgz",
@@ -1775,6 +1855,7 @@
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/anymatch/-/anymatch-2.0.0.tgz",
       "integrity": "sha512-5teOsQWABXHHBFP9y3skS5P3d/WfWXpv3FUpy+LorMrNYaT9pI4oLMQX7jzQ2KklNpGpWHzdCXTDT2Y3XGlZBw==",
+      "dev": true,
       "requires": {
         "micromatch": "^3.1.4",
         "normalize-path": "^2.1.1"
@@ -1784,6 +1865,7 @@
           "version": "2.1.1",
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+          "version": "2.1.6",
+          "resolved": "https://registry.npmjs.org/chokidar/-/chokidar-2.1.6.tgz",
+          "integrity": "sha512-V2jUo67OKkc6ySiRpJrjlpJKl9kDuG+Xb8VgsGzb+aEouhgS1D0weyPU4lEzdAcsCAvrih2J2BqyXqHWvVLw5g==",
+          "dev": true,
+          "requires": {
+            "anymatch": "^2.0.0",
+            "async-each": "^1.0.1",
+            "braces": "^2.3.2",
+            "fsevents": "^1.2.7",
+            "glob-parent": "^3.1.0",
+            "inherits": "^2.0.3",
+            "is-binary-path": "^1.0.0",
+            "is-glob": "^4.0.0",
+            "normalize-path": "^3.0.0",
+            "path-is-absolute": "^1.0.0",
+            "readdirp": "^2.2.1",
+            "upath": "^1.1.1"
+          }
+        },
+        "is-binary-path": {
+          "version": "1.0.1",
+          "resolved": "https://registry.npmjs.org/is-binary-path/-/is-binary-path-1.0.1.tgz",
+          "integrity": "sha1-dfFmQrSA8YenEcgUFh/TpKdlWJg=",
+          "dev": true,
+          "requires": {
+            "binary-extensions": "^1.0.0"
+          }
+        },
+        "readdirp": {
+          "version": "2.2.1",
+          "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-2.2.1.tgz",
+          "integrity": "sha512-1JU/8q+VgFZyxwrJ+SVIOsh+KywWGpds3NTqikiKpDMZWScmAYyKIgqkO+ARvNWJfXeXR1zxz7aHF4u4CyH6vQ==",
+          "dev": true,
+          "requires": {
+            "graceful-fs": "^4.1.11",
+            "micromatch": "^3.1.10",
+            "readable-stream": "^2.0.2"
+          }
+        }
       }
     },
     "wbuf": {
@@ -12312,12 +12715,12 @@
       }
     },
     "ws": {
-      "version": "6.2.1",
-      "resolved": "https://registry.npmjs.org/ws/-/ws-6.2.1.tgz",
-      "integrity": "sha512-GIyAXC2cB7LjvpgMt9EKS2ldqr0MTrORaleiOno6TweZ6r3TKtoFQWay/2PceJ3RuBasOHzXNn5Lrw1X0bEjqA==",
+      "version": "7.0.1",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-7.0.1.tgz",
+      "integrity": "sha512-ILHfMbuqLJvnSgYXLgy4kMntroJpe8hT41dOVWM8bxRuw6TK4mgMp9VJUNsZTEc5Bh+Mbs0DJT4M0N+wBG9l9A==",
       "dev": true,
       "requires": {
-        "async-limiter": "~1.0.0"
+        "async-limiter": "^1.0.0"
       }
     },
     "xml": {
diff --git a/package.json b/package.json
index f34c3ddf83..b3fe1355b0 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
     "client"
   ],
   "engines": {
-    "node": ">= 6.11.5"
+    "node": ">= 8.9.0"
   },
   "scripts": {
     "lint:prettier": "prettier \"{**/*,*}.{js,json,md,yml,css}\" --list-different",
@@ -37,11 +37,11 @@
   "dependencies": {
     "ansi-html": "0.0.7",
     "bonjour": "^3.5.0",
-    "chokidar": "^2.1.6",
+    "chokidar": "^3.0.1",
     "compression": "^1.7.4",
     "connect-history-api-fallback": "^1.6.0",
     "debug": "^4.1.1",
-    "del": "^4.1.1",
+    "del": "^5.0.0",
     "express": "^4.17.1",
     "html-entities": "^1.2.1",
     "http-proxy-middleware": "^0.19.1",
@@ -51,8 +51,8 @@
     "is-absolute-url": "^3.0.0",
     "killable": "^1.0.1",
     "loglevel": "^1.6.3",
-    "opn": "^5.5.0",
-    "p-retry": "^3.0.1",
+    "open": "^6.2.0",
+    "p-retry": "^4.1.0",
     "portfinder": "^1.0.20",
     "schema-utils": "^1.0.0",
     "selfsigned": "^1.10.4",
@@ -85,7 +85,7 @@
     "eslint-config-webpack": "^1.2.5",
     "eslint-plugin-import": "^2.17.3",
     "execa": "^1.0.0",
-    "file-loader": "^3.0.1",
+    "file-loader": "^4.0.0",
     "html-loader": "^0.5.5",
     "html-webpack-plugin": "^3.2.0",
     "husky": "^2.5.0",
@@ -105,10 +105,10 @@
     "style-loader": "^0.23.1",
     "supertest": "^4.0.2",
     "tcp-port-used": "^1.0.1",
-    "url-loader": "^1.1.2",
     "webpack": "^4.35.0",
     "webpack-cli": "^3.3.5",
-    "ws": "^6.2.1"
+    "url-loader": "^2.0.0",
+    "ws": "^7.0.0"
   },
   "peerDependencies": {
     "webpack": "^4.0.0"
diff --git a/test/cli/cli.test.js b/test/cli/cli.test.js
index 8bd1e04ddd..404cff789c 100644
--- a/test/cli/cli.test.js
+++ b/test/cli/cli.test.js
@@ -1,8 +1,8 @@
 'use strict';
 
-const { unlink } = require('fs');
 const { join, resolve } = require('path');
 const execa = require('execa');
+const { unlinkAsync } = require('../helpers/fs');
 const testBin = require('../helpers/test-bin');
 
 const httpsCertificateDirectory = resolve(
@@ -15,108 +15,74 @@ const keyPath = resolve(httpsCertificateDirectory, 'server.key');
 const certPath = resolve(httpsCertificateDirectory, 'server.crt');
 
 describe('CLI', () => {
-  it('--progress', (done) => {
-    testBin('--progress')
-      .then((output) => {
-        expect(output.code).toEqual(0);
-        expect(output.stderr.includes('0% compiling')).toBe(true);
-        done();
-      })
-      .catch(done);
+  it('--progress', async () => {
+    const { code, stderr } = await testBin('--progress');
+    expect(code).toEqual(0);
+    expect(stderr.includes('0% compiling')).toBe(true);
   });
 
-  it('--bonjour', (done) => {
-    testBin('--bonjour')
-      .then((output) => {
-        expect(output.code).toEqual(0);
-        expect(output.stdout.includes('Bonjour')).toBe(true);
-        done();
-      })
-      .catch(done);
+  it('--bonjour', async () => {
+    const { code, stdout } = await testBin('--bonjour');
+    expect(code).toEqual(0);
+    expect(stdout.includes('Bonjour')).toBe(true);
   });
 
-  it('--https', (done) => {
-    testBin('--https')
-      .then((output) => {
-        expect(output.code).toEqual(0);
-        expect(output.stdout.includes('Project is running at')).toBe(true);
-        done();
-      })
-      .catch(done);
+  it('--https', async () => {
+    const { code, stdout } = await testBin('--https');
+    expect(code).toEqual(0);
+    expect(stdout.includes('Project is running at')).toBe(true);
   });
 
-  it('--https --cacert --pfx --key --cert --pfx-passphrase', (done) => {
-    testBin(
+  it('--https --cacert --pfx --key --cert --pfx-passphrase', async () => {
+    const { code, stdout } = await testBin(
       `--https --cacert ${caPath} --pfx ${pfxPath} --key ${keyPath} --cert ${certPath} --pfx-passphrase webpack-dev-server`
-    )
-      .then((output) => {
-        expect(output.code).toEqual(0);
-        expect(output.stdout.includes('Project is running at')).toBe(true);
-        done();
-      })
-      .catch(done);
+    );
+    expect(code).toEqual(0);
+    expect(stdout.includes('Project is running at')).toBe(true);
   });
 
-  it('--sockPath', (done) => {
-    testBin('--sockPath /mysockPath')
-      .then((output) => {
-        expect(
-          output.stdout.includes('http://localhost&sockPath=/mysockPath')
-        ).toEqual(true);
-        done();
-      })
-      .catch(done);
+  it('--sockPath', async () => {
+    const { stdout } = await testBin('--sockPath /mysockPath');
+    expect(stdout.includes('http://localhost&sockPath=/mysockPath')).toBe(true);
   });
 
-  it('--color', (done) => {
-    testBin('--color')
-      .then((output) => {
-        // https://github.com/webpack/webpack-dev-server/blob/master/lib/utils/colors.js
-        expect(
-          output.stdout.includes('\u001b[39m \u001b[90m｢wds｣\u001b[39m:')
-        ).toEqual(true);
-        done();
-      })
-      .catch(done);
+  it('--color', async () => {
+    const { stdout } = await testBin('--color');
+    // https://github.com/webpack/webpack-dev-server/blob/master/lib/utils/colors.js
+    expect(stdout.includes('\u001b[39m \u001b[90m｢wds｣\u001b[39m:')).toBe(true);
   });
 
   // The Unix socket to listen to (instead of a host).
-  it('--socket', (done) => {
+  it('--socket', async () => {
     const socketPath = join('.', 'webpack.sock');
+    const { code, stdout } = await testBin(`--socket ${socketPath}`);
+    expect(code).toEqual(0);
 
-    testBin(`--socket ${socketPath}`)
-      .then((output) => {
-        expect(output.code).toEqual(0);
-
-        if (process.platform === 'win32') {
-          done();
-        } else {
-          expect(output.stdout.includes(socketPath)).toBe(true);
-
-          unlink(socketPath, () => {
-            done();
-          });
-        }
-      })
-      .catch(done);
+    if (process.platform !== 'win32') {
+      expect(stdout.includes(socketPath)).toBe(true);
+
+      await unlinkAsync(socketPath);
+    }
   });
 
-  it('should accept the promise function of webpack.config.js', (done) => {
-    testBin(
-      false,
-      resolve(__dirname, '../fixtures/promise-config/webpack.config.js')
-    )
-      .then((output) => {
-        expect(output.code).toEqual(0);
-        done();
-      })
-      .catch((err) => {
-        // for windows
-        expect(err.stdout.includes('Compiled successfully.')).toEqual(true);
-        done();
-      });
+  it('should accept the promise function of webpack.config.js', async () => {
+    try {
+      const { code } = await testBin(
+        false,
+        resolve(__dirname, '../fixtures/promise-config/webpack.config.js')
+      );
+      expect(code).toEqual(0);
+    } catch (err) {
+      // for windows
+      if (process.platform === 'win32') {
+        expect(err.stdout.includes('Compiled successfully.')).toBe(true);
+      } else {
+        throw err;
+      }
+    }
   });
 
+  // TODO: hiroppy
   it('should exit the process when SIGINT is detected', (done) => {
     const cliPath = resolve(__dirname, '../../bin/webpack-dev-server.js');
     const examplePath = resolve(__dirname, '../../examples/cli/public');
diff --git a/test/client/clients/SockJSClient.test.js b/test/client/clients/SockJSClient.test.js
index a5b667c03a..62817459da 100644
--- a/test/client/clients/SockJSClient.test.js
+++ b/test/client/clients/SockJSClient.test.js
@@ -4,6 +4,7 @@ const http = require('http');
 const express = require('express');
 const sockjs = require('sockjs');
 const SockJSClient = require('../../../client-src/clients/SockJSClient');
+const timer = require('../../helpers/timer');
 const port = require('../../ports-map').sockJSClient;
 
 describe('SockJSClient', () => {
@@ -25,13 +26,12 @@ describe('SockJSClient', () => {
   });
 
   describe('client', () => {
-    it('should open, receive message, and close', (done) => {
-      socketServer.on('connection', (connection) => {
+    it('should open, receive message, and close', async () => {
+      socketServer.on('connection', async (connection) => {
         connection.write('hello world');
 
-        setTimeout(() => {
-          connection.close();
-        }, 1000);
+        await timer(1000);
+        connection.close();
       });
 
       const client = new SockJSClient(`http://localhost:${port}/sockjs-node`);
@@ -47,19 +47,16 @@ describe('SockJSClient', () => {
         data.push(msg);
       });
 
-      setTimeout(() => {
-        expect(data.length).toEqual(3);
-        expect(data[0]).toEqual('open');
-        expect(data[1]).toEqual('hello world');
-        expect(data[2]).toEqual('close');
-        done();
-      }, 3000);
+      await timer(3000);
+
+      expect(data.length).toEqual(3);
+      expect(data[0]).toEqual('open');
+      expect(data[1]).toEqual('hello world');
+      expect(data[2]).toEqual('close');
     });
   });
 
   afterAll((done) => {
-    listeningApp.close(() => {
-      done();
-    });
+    listeningApp.close(done);
   });
 });
diff --git a/test/client/utils/__snapshots__/log.test.js.snap b/test/client/utils/__snapshots__/log.test.js.snap
index a62894e923..8f120617a2 100644
--- a/test/client/utils/__snapshots__/log.test.js.snap
+++ b/test/client/utils/__snapshots__/log.test.js.snap
@@ -19,8 +19,5 @@ Array [
   Array [
     "trace",
   ],
-  Array [
-    "warn",
-  ],
 ]
 `;
diff --git a/test/client/utils/createSocketUrl.test.js b/test/client/utils/createSocketUrl.test.js
index 892e8204eb..b521242c76 100644
--- a/test/client/utils/createSocketUrl.test.js
+++ b/test/client/utils/createSocketUrl.test.js
@@ -21,8 +21,10 @@ describe('createSocketUrl', () => {
       () => () => url
     );
 
-    // eslint-disable-next-line global-require
-    const createSocketUrl = require('../../../client-src/default/utils/createSocketUrl');
+    const {
+      default: createSocketUrl,
+      // eslint-disable-next-line global-require
+    } = require('../../../client-src/default/utils/createSocketUrl');
 
     test(`should return the url when __resourceQuery is ${url}`, () => {
       expect(createSocketUrl(url)).toMatchSnapshot();
diff --git a/test/client/utils/getCurrentScriptSource.test.js b/test/client/utils/getCurrentScriptSource.test.js
index 8fb953b1f3..b6c4f4d017 100644
--- a/test/client/utils/getCurrentScriptSource.test.js
+++ b/test/client/utils/getCurrentScriptSource.test.js
@@ -1,6 +1,8 @@
 'use strict';
 
-const getCurrentScriptSource = require('../../../client-src/default/utils/getCurrentScriptSource');
+const {
+  default: getCurrentScriptSource,
+} = require('../../../client-src/default/utils/getCurrentScriptSource');
 
 describe('getCurrentScriptSource', () => {
   afterEach(() => {
diff --git a/test/client/utils/log.test.js b/test/client/utils/log.test.js
index 79021d13d7..f72c6486b7 100644
--- a/test/client/utils/log.test.js
+++ b/test/client/utils/log.test.js
@@ -35,7 +35,7 @@ describe('log', () => {
   });
 
   test('should set log level via setLogLevel', () => {
-    ['info', 'warn', 'error', 'debug', 'trace', 'warning'].forEach((level) => {
+    ['info', 'warn', 'error', 'debug', 'trace'].forEach((level) => {
       setLogLevel(level);
     });
 
@@ -44,14 +44,12 @@ describe('log', () => {
     ).toMatchSnapshot();
   });
 
-  test('should set none and silent via setLogLevel', () => {
-    ['none', 'silent'].forEach((level) => {
-      setLogLevel(level);
-    });
+  test('should set silent via setLogLevel', () => {
+    setLogLevel('silent');
 
     expect(
       logMock.getLogger.mock.results[0].value.disableAll.mock.results
-    ).toHaveLength(2);
+    ).toHaveLength(1);
   });
 
   test('should output exception log when the level is unknown', () => {
diff --git a/test/client/utils/reloadApp.test.js b/test/client/utils/reloadApp.test.js
index 13a392b117..9686dddf70 100644
--- a/test/client/utils/reloadApp.test.js
+++ b/test/client/utils/reloadApp.test.js
@@ -25,7 +25,7 @@ describe('reloadApp', () => {
     });
 
     // eslint-disable-next-line global-require
-    reloadApp = require('../../../client-src/default/utils/reloadApp');
+    reloadApp = require('../../../client-src/default/utils/reloadApp').default;
   });
 
   afterEach(() => {
diff --git a/test/client/utils/sendMessage.test.js b/test/client/utils/sendMessage.test.js
index a60f2548bc..17cbb4ea61 100644
--- a/test/client/utils/sendMessage.test.js
+++ b/test/client/utils/sendMessage.test.js
@@ -2,7 +2,9 @@
 
 /* global self */
 
-const sendMessage = require('../../../client-src/default/utils/sendMessage');
+const {
+  default: sendMessage,
+} = require('../../../client-src/default/utils/sendMessage');
 
 describe('sendMessage', () => {
   afterEach(() => {
diff --git a/test/e2e/Client.test.js b/test/e2e/Client.test.js
index 90eb2ffe5a..3995fec5a6 100644
--- a/test/e2e/Client.test.js
+++ b/test/e2e/Client.test.js
@@ -37,56 +37,50 @@ describe('reload', () => {
     });
 
     describe('on browser client', () => {
-      it('should hot reload without page refresh', (done) => {
-        runBrowser().then(({ page, browser }) => {
-          let refreshed = false;
-          page.waitForNavigation({ waitUntil: 'load' }).then(() => {
-            page
-              .evaluate(() => {
-                const body = document.body;
-                const bgColor = getComputedStyle(body)['background-color'];
-                return bgColor;
-              })
-              .then((color) => {
-                page.setRequestInterception(true).then(() => {
-                  page.on('request', (req) => {
-                    if (
-                      req.isNavigationRequest() &&
-                      req.frame() === page.mainFrame() &&
-                      req.url() === `http://localhost:${port}/main`
-                    ) {
-                      refreshed = true;
-                    }
-                    req.continue();
-                  });
-                  fs.writeFileSync(
-                    cssFilePath,
-                    'body { background-color: rgb(255, 0, 0); }'
-                  );
-                  page.waitFor(10000).then(() => {
-                    page
-                      .evaluate(() => {
-                        const body = document.body;
-                        const bgColor = getComputedStyle(body)[
-                          'background-color'
-                        ];
-                        return bgColor;
-                      })
-                      .then((color2) => {
-                        browser.close().then(() => {
-                          expect(color).toEqual('rgb(0, 0, 255)');
-                          expect(color2).toEqual('rgb(255, 0, 0)');
-                          expect(refreshed).toBeFalsy();
-                          done();
-                        });
-                      });
-                  });
-                });
-              });
-          });
-
-          page.goto(`http://localhost:${port}/main`);
+      it('should hot reload without page refresh', async () => {
+        let refreshed = false;
+        const { page, browser } = await runBrowser();
+
+        page.goto(`http://localhost:${port}/main`);
+
+        await page.waitForNavigation({ waitUntil: 'load' });
+
+        const color = await page.evaluate(() => {
+          const body = document.body;
+          const bgColor = getComputedStyle(body)['background-color'];
+          return bgColor;
+        });
+
+        await page.setRequestInterception(true);
+
+        page.on('request', (req) => {
+          if (
+            req.isNavigationRequest() &&
+            req.frame() === page.mainFrame() &&
+            req.url() === `http://localhost:${port}/main`
+          ) {
+            refreshed = true;
+          }
+          req.continue();
         });
+        fs.writeFileSync(
+          cssFilePath,
+          'body { background-color: rgb(255, 0, 0); }'
+        );
+
+        await page.waitFor(10000);
+
+        const color2 = await page.evaluate(() => {
+          const body = document.body;
+          const bgColor = getComputedStyle(body)['background-color'];
+          return bgColor;
+        });
+
+        await browser.close();
+
+        expect(color).toEqual('rgb(0, 0, 255)');
+        expect(color2).toEqual('rgb(255, 0, 0)');
+        expect(refreshed).toBeFalsy();
       });
     });
   });
@@ -115,56 +109,50 @@ describe('reload', () => {
     });
 
     describe('on browser client', () => {
-      it('should reload with page refresh', (done) => {
-        runBrowser().then(({ page, browser }) => {
-          let refreshed = false;
-          page.waitForNavigation({ waitUntil: 'load' }).then(() => {
-            page
-              .evaluate(() => {
-                const body = document.body;
-                const bgColor = getComputedStyle(body)['background-color'];
-                return bgColor;
-              })
-              .then((color) => {
-                page.setRequestInterception(true).then(() => {
-                  page.on('request', (req) => {
-                    if (
-                      req.isNavigationRequest() &&
-                      req.frame() === page.mainFrame() &&
-                      req.url() === `http://localhost:${port}/main`
-                    ) {
-                      refreshed = true;
-                    }
-                    req.continue();
-                  });
-                  fs.writeFileSync(
-                    cssFilePath,
-                    'body { background-color: rgb(255, 0, 0); }'
-                  );
-                  page.waitFor(10000).then(() => {
-                    page
-                      .evaluate(() => {
-                        const body = document.body;
-                        const bgColor = getComputedStyle(body)[
-                          'background-color'
-                        ];
-                        return bgColor;
-                      })
-                      .then((color2) => {
-                        browser.close().then(() => {
-                          expect(color).toEqual('rgb(0, 0, 255)');
-                          expect(color2).toEqual('rgb(255, 0, 0)');
-                          expect(refreshed).toBeTruthy();
-                          done();
-                        });
-                      });
-                  });
-                });
-              });
-          });
-
-          page.goto(`http://localhost:${port}/main`);
+      it('should reload with page refresh', async () => {
+        let refreshed = false;
+        const { page, browser } = await runBrowser();
+
+        page.goto(`http://localhost:${port}/main`);
+
+        await page.waitForNavigation({ waitUntil: 'load' });
+
+        const color = await page.evaluate(() => {
+          const body = document.body;
+          const bgColor = getComputedStyle(body)['background-color'];
+          return bgColor;
+        });
+
+        await page.setRequestInterception(true);
+
+        page.on('request', (req) => {
+          if (
+            req.isNavigationRequest() &&
+            req.frame() === page.mainFrame() &&
+            req.url() === `http://localhost:${port}/main`
+          ) {
+            refreshed = true;
+          }
+          req.continue();
         });
+        fs.writeFileSync(
+          cssFilePath,
+          'body { background-color: rgb(255, 0, 0); }'
+        );
+
+        await page.waitFor(10000);
+
+        const color2 = await page.evaluate(() => {
+          const body = document.body;
+          const bgColor = getComputedStyle(body)['background-color'];
+          return bgColor;
+        });
+
+        await browser.close();
+
+        expect(color).toEqual('rgb(0, 0, 255)');
+        expect(color2).toEqual('rgb(255, 0, 0)');
+        expect(refreshed).toBeTruthy();
       });
     });
   });
diff --git a/test/e2e/ClientOptions.test.js b/test/e2e/ClientOptions.test.js
index 07d3bba8d9..9c7f119a48 100644
--- a/test/e2e/ClientOptions.test.js
+++ b/test/e2e/ClientOptions.test.js
@@ -7,6 +7,7 @@ const testServer = require('../helpers/test-server');
 const config = require('../fixtures/client-config/webpack.config');
 const runBrowser = require('../helpers/run-browser');
 const [port1, port2, port3] = require('../ports-map').ClientOptions;
+const timer = require('../helpers/timer');
 
 describe('Client code', () => {
   function startProxy(port) {
@@ -48,38 +49,33 @@ describe('Client code', () => {
     });
 
     afterAll((done) => {
-      proxy.close(() => {
-        done();
-      });
+      proxy.close(done);
     });
 
-    it('responds with a 200', (done) => {
+    it('responds with a 200', async () => {
       {
         const req = request(`http://localhost:${port2}`);
-        req.get('/sockjs-node').expect(200, 'Welcome to SockJS!\n', done);
+        await req.get('/sockjs-node').expect(200, 'Welcome to SockJS!\n');
       }
       {
         const req = request(`http://localhost:${port1}`);
-        req.get('/sockjs-node').expect(200, 'Welcome to SockJS!\n', done);
+        await req.get('/sockjs-node').expect(200, 'Welcome to SockJS!\n');
       }
     });
 
-    it('requests websocket through the proxy with proper port number', (done) => {
-      runBrowser().then(({ page, browser }) => {
-        page
-          .waitForRequest((requestObj) => requestObj.url().match(/sockjs-node/))
-          .then((requestObj) => {
-            browser.close().then(() => {
-              expect(
-                requestObj
-                  .url()
-                  .includes(`http://localhost:${port1}/sockjs-node`)
-              ).toBeTruthy();
-              done();
-            });
-          });
-        page.goto(`http://localhost:${port2}/main`);
-      });
+    it('requests websocket through the proxy with proper port number', async () => {
+      const { page, browser } = await runBrowser();
+
+      page.goto(`http://localhost:${port2}/main`);
+      const req = await page.waitForRequest((requestObj) =>
+        requestObj.url().match(/sockjs-node/)
+      );
+
+      await browser.close();
+
+      expect(
+        req.url().includes(`http://localhost:${port1}/sockjs-node`)
+      ).toBeTruthy();
     });
   });
 });
@@ -102,24 +98,20 @@ describe('Client complex inline script path', () => {
   afterAll(testServer.close);
 
   describe('browser client', () => {
-    it('uses the correct public hostname and sockPath', (done) => {
-      runBrowser().then(({ page, browser }) => {
-        page
-          .waitForRequest((requestObj) =>
-            requestObj.url().match(/foo\/test\/bar/)
-          )
-          .then((requestObj) => {
-            browser.close().then(() => {
-              expect(
-                requestObj
-                  .url()
-                  .includes(`http://myhost.test:${port2}/foo/test/bar/`)
-              ).toBeTruthy();
-              done();
-            });
-          });
-        page.goto(`http://localhost:${port2}/main`);
-      });
+    it('uses the correct public hostname and sockPath', async () => {
+      const { page, browser } = await runBrowser();
+
+      page.goto(`http://localhost:${port2}/main`);
+
+      const req = await page.waitForRequest((requestObj) =>
+        requestObj.url().match(/foo\/test\/bar/)
+      );
+
+      await browser.close();
+
+      expect(
+        req.url().includes(`http://myhost.test:${port2}/foo/test/bar/`)
+      ).toBeTruthy();
     });
   });
 });
@@ -142,25 +134,20 @@ describe('Client complex inline script path with sockPort', () => {
   afterAll(testServer.close);
 
   describe('browser client', () => {
-    it('uses the correct sockPort', (done) => {
-      runBrowser().then(({ page, browser }) => {
-        page
-          .waitForRequest((requestObj) =>
-            requestObj.url().match(/foo\/test\/bar/)
-          )
-          .then((requestObj) => {
-            browser.close().then(() => {
-              expect(
-                requestObj
-                  .url()
-                  .includes(`http://localhost:${port3}/foo/test/bar`)
-              ).toBeTruthy();
-              done();
-            });
-          });
-
-        page.goto(`http://localhost:${port2}/main`);
-      });
+    it('uses the correct sockPort', async () => {
+      const { page, browser } = await runBrowser();
+
+      page.goto(`http://localhost:${port2}/main`);
+
+      const req = await page.waitForRequest((requestObj) =>
+        requestObj.url().match(/foo\/test\/bar/)
+      );
+
+      await browser.close();
+
+      expect(
+        req.url().includes(`http://localhost:${port3}/foo/test/bar`)
+      ).toBeTruthy();
     });
   });
 });
@@ -185,22 +172,19 @@ describe('Client complex inline script path with sockPort, no sockPath', () => {
   afterAll(testServer.close);
 
   describe('browser client', () => {
-    it('uses the correct sockPort and sockPath', (done) => {
-      runBrowser().then(({ page, browser }) => {
-        page
-          .waitForRequest((requestObj) => requestObj.url().match(/sockjs-node/))
-          .then((requestObj) => {
-            browser.close().then(() => {
-              expect(
-                requestObj
-                  .url()
-                  .includes(`http://localhost:${port3}/sockjs-node`)
-              ).toBeTruthy();
-              done();
-            });
-          });
-        page.goto(`http://localhost:${port2}/main`);
-      });
+    it('uses the correct sockPort and sockPath', async () => {
+      const { page, browser } = await runBrowser();
+
+      page.goto(`http://localhost:${port2}/main`);
+      const req = await page.waitForRequest((requestObj) =>
+        requestObj.url().match(/sockjs-node/)
+      );
+
+      await browser.close();
+
+      expect(
+        req.url().includes(`http://localhost:${port3}/sockjs-node`)
+      ).toBeTruthy();
     });
   });
 });
@@ -222,22 +206,19 @@ describe('Client complex inline script path with sockHost', () => {
   afterAll(testServer.close);
 
   describe('browser client', () => {
-    it('uses the correct sockHost', (done) => {
-      runBrowser().then(({ page, browser }) => {
-        page
-          .waitForRequest((requestObj) => requestObj.url().match(/sockjs-node/))
-          .then((requestObj) => {
-            browser.close().then(() => {
-              expect(
-                requestObj
-                  .url()
-                  .includes(`http://myhost.test:${port2}/sockjs-node`)
-              ).toBeTruthy();
-              done();
-            });
-          });
-        page.goto(`http://localhost:${port2}/main`);
-      });
+    it('uses the correct sockHost', async () => {
+      const { page, browser } = await runBrowser();
+
+      page.goto(`http://localhost:${port2}/main`);
+
+      const req = await page.waitForRequest((requestObj) =>
+        requestObj.url().match(/sockjs-node/)
+      );
+      await browser.close();
+
+      expect(
+        req.url().includes(`http://myhost.test:${port2}/sockjs-node`)
+      ).toBeTruthy();
     });
   });
 });
@@ -281,37 +262,31 @@ describe('Client console.log', () => {
   ];
 
   for (const { title, options } of cases) {
-    it(title, () => {
+    it(title, async () => {
       const res = [];
       const testOptions = Object.assign({}, baseOptions, options);
 
-      // TODO: use async/await when Node.js v6 support is dropped
-      return Promise.resolve()
-        .then(() => {
-          return new Promise((resolve) => {
-            testServer.startAwaitingCompilation(config, testOptions, resolve);
-          });
-        })
-        .then(runBrowser)
-        .then(({ page, browser }) => {
-          return new Promise((resolve) => {
-            page.goto(`http://localhost:${port2}/main`);
-            page.on('console', ({ _text }) => {
-              res.push(_text);
-            });
-            setTimeout(() => {
-              browser.close().then(() => {
-                expect(res).toMatchSnapshot();
-                resolve();
-              });
-            }, 1000);
-          });
-        })
-        .then(() => {
-          return new Promise((resolve) => {
-            testServer.close(resolve);
-          });
-        });
+      // TODO: refactor(hiroppy)
+      await new Promise((resolve) => {
+        testServer.startAwaitingCompilation(config, testOptions, resolve);
+      });
+
+      const { page, browser } = await runBrowser();
+
+      page.goto(`http://localhost:${port2}/main`);
+      page.on('console', ({ _text }) => {
+        res.push(_text);
+      });
+
+      await timer(3000);
+
+      expect(res).toMatchSnapshot();
+      await browser.close();
+
+      // TODO: refactor(hiroppy)
+      await new Promise((resolve) => {
+        testServer.close(resolve);
+      });
     });
   }
 });
diff --git a/test/e2e/ProvidePlugin.test.js b/test/e2e/ProvidePlugin.test.js
index 99d44cf910..38eaa089dd 100644
--- a/test/e2e/ProvidePlugin.test.js
+++ b/test/e2e/ProvidePlugin.test.js
@@ -22,22 +22,19 @@ describe('ProvidePlugin', () => {
     afterAll(testServer.close);
 
     describe('on browser client', () => {
-      it('should inject SockJS client implementation', (done) => {
-        runBrowser().then(({ page, browser }) => {
-          page.waitForNavigation({ waitUntil: 'load' }).then(() => {
-            page
-              .evaluate(() => {
-                return window.injectedClient === window.expectedClient;
-              })
-              .then((isCorrectClient) => {
-                browser.close().then(() => {
-                  expect(isCorrectClient).toBeTruthy();
-                  done();
-                });
-              });
-          });
-          page.goto(`http://localhost:${port}/main`);
+      it('should inject SockJS client implementation', async () => {
+        const { page, browser } = await runBrowser();
+
+        page.goto(`http://localhost:${port}/main`);
+        await page.waitForNavigation({ waitUntil: 'load' });
+
+        const isCorrectClient = await page.evaluate(() => {
+          return window.injectedClient === window.expectedClient;
         });
+
+        await browser.close();
+
+        expect(isCorrectClient).toBeTruthy();
       });
     });
   });
@@ -58,23 +55,21 @@ describe('ProvidePlugin', () => {
     afterAll(testServer.close);
 
     describe('on browser client', () => {
-      it('should not inject client implementation', (done) => {
-        runBrowser().then(({ page, browser }) => {
-          page.waitForNavigation({ waitUntil: 'load' }).then(() => {
-            page
-              .evaluate(() => {
-                // eslint-disable-next-line no-undefined
-                return window.injectedClient === undefined;
-              })
-              .then((isCorrectClient) => {
-                browser.close().then(() => {
-                  expect(isCorrectClient).toBeTruthy();
-                  done();
-                });
-              });
-          });
-          page.goto(`http://localhost:${port}/main`);
+      it('should not inject client implementation', async () => {
+        const { page, browser } = await runBrowser();
+
+        page.goto(`http://localhost:${port}/main`);
+
+        await page.waitForNavigation({ waitUntil: 'load' });
+
+        const isCorrectClient = await page.evaluate(() => {
+          // eslint-disable-next-line no-undefined
+          return window.injectedClient === undefined;
         });
+
+        await browser.close();
+
+        expect(isCorrectClient).toBeTruthy();
       });
     });
   });
diff --git a/test/helpers/fs.js b/test/helpers/fs.js
new file mode 100644
index 0000000000..d715846748
--- /dev/null
+++ b/test/helpers/fs.js
@@ -0,0 +1,15 @@
+// we'll delete this file when Node8 is not supported.
+// because we can use fs.promise
+
+'use strict';
+
+const { promisify } = require('util');
+const { writeFile, unlink } = require('fs');
+
+const unlinkAsync = promisify(unlink);
+const writeAsync = promisify(writeFile);
+
+module.exports = {
+  unlinkAsync,
+  writeAsync,
+};
diff --git a/test/helpers/run-browser.js b/test/helpers/run-browser.js
index 53993d88d1..9e36ca5d11 100644
--- a/test/helpers/run-browser.js
+++ b/test/helpers/run-browser.js
@@ -2,7 +2,7 @@
 
 const puppeteer = require('puppeteer');
 
-function runBrowser(config) {
+async function runBrowser(config) {
   const options = {
     viewport: {
       width: 500,
@@ -12,26 +12,15 @@ function runBrowser(config) {
     ...config,
   };
 
-  return new Promise((resolve, reject) => {
-    let page;
-    let browser;
-
-    puppeteer
-      .launch({
-        headless: true,
-        args: ['--no-sandbox', '--disable-setuid-sandbox'],
-      })
-      .then((launchedBrowser) => {
-        browser = launchedBrowser;
-        return browser.newPage();
-      })
-      .then((newPage) => {
-        page = newPage;
-        page.emulate(options);
-        resolve({ page, browser });
-      })
-      .catch(reject);
+  const launchedBrowser = await puppeteer.launch({
+    headless: true,
+    args: ['--no-sandbox', '--disable-setuid-sandbox'],
   });
+  const browser = launchedBrowser;
+  const page = await browser.newPage();
+  page.emulate(options);
+
+  return { page, browser };
 }
 
 module.exports = runBrowser;
diff --git a/test/helpers/timer.js b/test/helpers/timer.js
new file mode 100644
index 0000000000..0608301ec8
--- /dev/null
+++ b/test/helpers/timer.js
@@ -0,0 +1,11 @@
+'use strict';
+
+function timer(t) {
+  return new Promise((resolve) => {
+    setTimeout(() => {
+      resolve();
+    }, t);
+  });
+}
+
+module.exports = timer;
diff --git a/test/integration/MultiCompiler.test.js b/test/integration/MultiCompiler.test.js
index 5d9cc9c15b..d35fe9ba78 100644
--- a/test/integration/MultiCompiler.test.js
+++ b/test/integration/MultiCompiler.test.js
@@ -17,10 +17,10 @@ describe('multi compiler', () => {
   afterAll(testServer.close);
 
   // TODO: this is a very basic test, optimally it should test multiple configs etc.
-  it('should handle GET request to bundle', (done) => {
-    req
+  it('should handle GET request to bundle', async () => {
+    await req
       .get('/main.js')
       .expect('Content-Type', 'application/javascript; charset=UTF-8')
-      .expect(200, done);
+      .expect(200);
   });
 });
diff --git a/test/integration/UniversalCompiler.test.js b/test/integration/UniversalCompiler.test.js
index 81225c3ad1..3ae2c3bd7a 100644
--- a/test/integration/UniversalCompiler.test.js
+++ b/test/integration/UniversalCompiler.test.js
@@ -16,35 +16,33 @@ describe('universal compiler', () => {
 
   afterAll(testServer.close);
 
-  it('client bundle should have the inlined the client runtime', (done) => {
-    req
+  it('client bundle should have the inlined the client runtime', async () => {
+    const { res, err } = await req
       .get('/client.js')
       .expect('Content-Type', 'application/javascript; charset=UTF-8')
-      .expect(200)
-      .end((err, res) => {
-        if (err) {
-          return done(err);
-        }
-        expect(res.text).toContain('Hello from the client');
-        expect(res.text).toContain('sockjs-client');
-        done();
-      });
+      .expect(200);
+
+    if (err) {
+      throw err;
+    }
+
+    expect(res.text).toContain('Hello from the client');
+    expect(res.text).toContain('sockjs-client');
   });
 
-  it('server bundle should NOT have the inlined the client runtime', (done) => {
+  it('server bundle should NOT have the inlined the client runtime', async () => {
     // we wouldn't normally request a server bundle
     // but we'll do it here to check the contents
-    req
+    const { res, err } = await req
       .get('/server.js')
       .expect('Content-Type', 'application/javascript; charset=UTF-8')
-      .expect(200)
-      .end((err, res) => {
-        if (err) {
-          return done(err);
-        }
-        expect(res.text).toContain('Hello from the server');
-        expect(res.text).not.toContain('sockjs-client');
-        done();
-      });
+      .expect(200);
+
+    if (err) {
+      throw err;
+    }
+
+    expect(res.text).toContain('Hello from the server');
+    expect(res.text).not.toContain('sockjs-client');
   });
 });
diff --git a/test/options.test.js b/test/options.test.js
index 7e59879bb0..d63827cc56 100644
--- a/test/options.test.js
+++ b/test/options.test.js
@@ -23,75 +23,7 @@ describe('options', () => {
     expect(res).toEqual(true);
   });
 
-  describe('validation', () => {
-    let server;
-
-    afterAll((done) => {
-      if (server) {
-        server.close(() => {
-          done();
-        });
-      }
-    });
-
-    function validateOption(propertyName, cases) {
-      const successCount = cases.success.length;
-      const testCases = [];
-
-      for (const key of Object.keys(cases)) {
-        testCases.push(...cases[key]);
-      }
-
-      let current = 0;
-
-      return testCases.reduce((p, value) => {
-        let compiler = webpack(config);
-
-        return p
-          .then(() => {
-            const opts =
-              Object.prototype.toString.call(value) === '[object Object]' &&
-              Object.keys(value).length !== 0
-                ? value
-                : {
-                    [propertyName]: value,
-                  };
-
-            server = new Server(compiler, opts);
-          })
-          .then(() => {
-            if (current < successCount) {
-              expect(true).toBeTruthy();
-            } else {
-              expect(false).toBeTruthy();
-            }
-          })
-          .catch((err) => {
-            if (current >= successCount) {
-              expect(err).toBeInstanceOf(ValidationError);
-            } else {
-              expect(false).toBeTruthy();
-            }
-          })
-          .then(() => {
-            return new Promise((resolve) => {
-              if (server) {
-                server.close(() => {
-                  compiler = null;
-                  server = null;
-                  resolve();
-                });
-              } else {
-                resolve();
-              }
-            });
-          })
-          .then(() => {
-            current += 1;
-          });
-      }, Promise.resolve());
-    }
-
+  {
     const memfs = createFsFromVolume(new Volume());
     // We need to patch memfs
     // https://github.com/webpack/webpack-dev-middleware#fs
@@ -123,19 +55,8 @@ describe('options', () => {
         failure: [false],
       },
       clientLogLevel: {
-        success: [
-          'silent',
-          'info',
-          'error',
-          'warn',
-          'trace',
-          'debug',
-          // deprecated
-          'none',
-          // deprecated
-          'warning',
-        ],
-        failure: ['whoops!'],
+        success: ['silent', 'info', 'error', 'warn', 'trace', 'debug'],
+        failure: ['whoops!', 'none', 'warning'],
       },
       compress: {
         success: [true],
@@ -414,10 +335,58 @@ describe('options', () => {
       },
     };
 
-    Object.keys(cases).forEach((key) => {
-      it(key, () => {
-        return validateOption(key, cases[key]);
+    for (const [key, values] of Object.entries(cases)) {
+      it(`should validate "${key}" option`, async () => {
+        const compiler = webpack(config);
+        const { success, failure } = values;
+
+        for (const sample of success) {
+          let server;
+
+          try {
+            server = new Server(compiler, createOptions(key, sample));
+            expect(true).toBeTruthy();
+          } catch (e) {
+            expect(false).toBeTruthy();
+          }
+
+          // eslint-disable-next-line no-await-in-loop
+          await closeServer(server);
+        }
+
+        for (const sample of failure) {
+          let server;
+
+          try {
+            server = new Server(compiler, createOptions(key, sample));
+            expect(false).toBeTruthy();
+          } catch (e) {
+            expect(e).toBeInstanceOf(ValidationError);
+          }
+
+          // eslint-disable-next-line no-await-in-loop
+          await closeServer(server);
+        }
       });
+    }
+  }
+
+  function createOptions(key, value) {
+    return Object.prototype.toString.call(value) === '[object Object]' &&
+      Object.keys(value).length !== 0
+      ? value
+      : {
+          [key]: value,
+        };
+  }
+
+  async function closeServer(server) {
+    await new Promise((resolve) => {
+      if (server) {
+        server.close(resolve);
+      } else {
+        resolve();
+      }
     });
-  });
+  }
 });
diff --git a/test/ports-map.js b/test/ports-map.js
index eee60008e4..94559e3b6d 100644
--- a/test/ports-map.js
+++ b/test/ports-map.js
@@ -40,9 +40,7 @@ const portsList = {
 let startPort = 8079;
 const ports = {};
 
-Object.keys(portsList).forEach((key) => {
-  const value = portsList[key];
-
+Object.entries(portsList).forEach(([key, value]) => {
   ports[key] =
     value === 1
       ? (startPort += 1)
diff --git a/test/server/after-option.test.js b/test/server/after-option.test.js
index b9d57616d0..07e7fd5545 100644
--- a/test/server/after-option.test.js
+++ b/test/server/after-option.test.js
@@ -39,13 +39,12 @@ describe('after option', () => {
 
   afterAll(testServer.close);
 
-  it('should handle after route', () => {
-    return req
+  it('should handle after route', async () => {
+    const res = await req
       .get('/after/some/path')
       .expect('Content-Type', 'text/html; charset=utf-8')
-      .expect(200)
-      .then((response) => {
-        expect(response.text).toBe('after');
-      });
+      .expect(200);
+
+    expect(res.text).toBe('after');
   });
 });
diff --git a/test/server/before-option.test.js b/test/server/before-option.test.js
index 3da0ecfd54..4e831133c2 100644
--- a/test/server/before-option.test.js
+++ b/test/server/before-option.test.js
@@ -39,13 +39,12 @@ describe('before option', () => {
 
   afterAll(testServer.close);
 
-  it('should handle before route', () => {
-    return req
+  it('should handle before route', async () => {
+    const res = await req
       .get('/before/some/path')
       .expect('Content-Type', 'text/html; charset=utf-8')
-      .expect(200)
-      .then((response) => {
-        expect(response.text).toBe('before');
-      });
+      .expect(200);
+
+    expect(res.text).toBe('before');
   });
 });
diff --git a/test/server/compress-option.test.js b/test/server/compress-option.test.js
index 0a04d1466f..644d40356f 100644
--- a/test/server/compress-option.test.js
+++ b/test/server/compress-option.test.js
@@ -22,15 +22,15 @@ describe('compress option', () => {
 
     afterAll(testServer.close);
 
-    it('request to bundle file', (done) => {
-      req
+    it('request to bundle file', async () => {
+      await req
         .get('/main.js')
         .expect((res) => {
           if (res.header['content-encoding']) {
             throw new Error('Expected `content-encoding` header is undefined.');
           }
         })
-        .expect(200, done);
+        .expect(200);
     });
   });
 
@@ -49,11 +49,11 @@ describe('compress option', () => {
 
     afterAll(testServer.close);
 
-    it('request to bundle file', (done) => {
-      req
+    it('request to bundle file', async () => {
+      await req
         .get('/main.js')
         .expect('Content-Encoding', 'gzip')
-        .expect(200, done);
+        .expect(200);
     });
   });
 
@@ -72,15 +72,15 @@ describe('compress option', () => {
 
     afterAll(testServer.close);
 
-    it('request to bundle file', (done) => {
-      req
+    it('request to bundle file', async () => {
+      await req
         .get('/main.js')
         .expect((res) => {
           if (res.header['content-encoding']) {
             throw new Error('Expected `content-encoding` header is undefined.');
           }
         })
-        .expect(200, done);
+        .expect(200);
     });
   });
 });
diff --git a/test/server/contentBase-option.test.js b/test/server/contentBase-option.test.js
index baa4111124..00619a657a 100644
--- a/test/server/contentBase-option.test.js
+++ b/test/server/contentBase-option.test.js
@@ -37,19 +37,17 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
 
       fs.truncateSync(nestedFile);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, /Heyo/, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200, /Heyo/);
     });
 
-    it('Request to other file', (done) => {
-      req.get('/other.html').expect(200, /Other html/, done);
+    it('Request to other file', async () => {
+      await req.get('/other.html').expect(200, /Other html/);
     });
 
     it('Watches folder recursively', (done) => {
@@ -108,12 +106,12 @@ describe('contentBase option', () => {
       });
     });
 
-    it("shouldn't list the files inside the assets folder (404)", (done) => {
-      req.get('/assets/').expect(404, done);
+    it("shouldn't list the files inside the assets folder (404)", async () => {
+      await req.get('/assets/').expect(404);
     });
 
-    it('should show Heyo. because bar has index.html inside it (200)', (done) => {
-      req.get('/bar/').expect(200, /Heyo/, done);
+    it('should show Heyo. because bar has index.html inside it (200)', async () => {
+      await req.get('/bar/').expect(200, /Heyo/);
     });
   });
 
@@ -133,17 +131,15 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('should list the files inside the assets folder (200)', (done) => {
-      req.get('/assets/').expect(200, done);
+    it('should list the files inside the assets folder (200)', async () => {
+      await req.get('/assets/').expect(200);
     });
 
-    it('should show Heyo. because bar has index.html inside it (200)', (done) => {
-      req.get('/bar/').expect(200, /Heyo/, done);
+    it('should show Heyo. because bar has index.html inside it (200)', async () => {
+      await req.get('/bar/').expect(200, /Heyo/);
     });
   });
 
@@ -162,17 +158,15 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('should list the files inside the assets folder (200)', (done) => {
-      req.get('/assets/').expect(200, done);
+    it('should list the files inside the assets folder (200)', async () => {
+      await req.get('/assets/').expect(200);
     });
 
-    it('should show Heyo. because bar has index.html inside it (200)', (done) => {
-      req.get('/bar/').expect(200, /Heyo/, done);
+    it('should show Heyo. because bar has index.html inside it (200)', async () => {
+      await req.get('/bar/').expect(200, /Heyo/);
     });
   });
 
@@ -190,17 +184,15 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('Request to first directory', (done) => {
-      req.get('/').expect(200, /Heyo/, done);
+    it('Request to first directory', async () => {
+      await req.get('/').expect(200, /Heyo/);
     });
 
-    it('Request to second directory', (done) => {
-      req.get('/foo.html').expect(200, /Foo!/, done);
+    it('Request to second directory', async () => {
+      await req.get('/foo.html').expect(200, /Foo!/);
     });
   });
 
@@ -218,16 +210,14 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('Request to page', (done) => {
-      req
+    it('Request to page', async () => {
+      await req
         .get('/other.html')
         .expect('Location', '//localhost:9099999/other.html')
-        .expect(302, done);
+        .expect(302);
     });
   });
 
@@ -245,25 +235,23 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('Request to page', (done) => {
-      req
+    it('Request to page', async () => {
+      await req
         .get('/foo.html')
         // TODO: hmm, two slashes seems to be a bug?
         .expect('Location', 'http://example.com//foo.html')
-        .expect(302, done);
+        .expect(302);
     });
 
-    it('Request to page with search params', (done) => {
-      req
+    it('Request to page with search params', async () => {
+      await req
         .get('/foo.html?space=ship')
         // TODO: hmm, two slashes seems to be a bug?
         .expect('Location', 'http://example.com//foo.html?space=ship')
-        .expect(302, done);
+        .expect(302);
     });
   });
 
@@ -271,18 +259,16 @@ describe('contentBase option', () => {
     beforeAll((done) => {
       jest.spyOn(process, 'cwd').mockImplementation(() => contentBasePublic);
 
-      server = testServer.start(config, {}, done);
+      server = testServer.start(config, { port }, done);
       req = request(server.app);
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('Request to page', (done) => {
-      req.get('/other.html').expect(200, done);
+    it('Request to page', async () => {
+      await req.get('/other.html').expect(200);
     });
   });
 
@@ -304,13 +290,11 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('Request to page', (done) => {
-      req.get('/other.html').expect(404, done);
+    it('Request to page', async () => {
+      await req.get('/other.html').expect(404);
     });
   });
 
@@ -328,13 +312,11 @@ describe('contentBase option', () => {
     });
 
     afterAll((done) => {
-      testServer.close(() => {
-        done();
-      });
+      testServer.close(done);
     });
 
-    it('Request foo.wasm', (done) => {
-      req.get('/foo.wasm').expect('Content-Type', 'application/wasm', done);
+    it('Request foo.wasm', async () => {
+      await req.get('/foo.wasm').expect('Content-Type', 'application/wasm');
     });
   });
 });
diff --git a/test/server/headers-option.test.js b/test/server/headers-option.test.js
index 1f3f7ad6fa..1891fe01a2 100644
--- a/test/server/headers-option.test.js
+++ b/test/server/headers-option.test.js
@@ -24,11 +24,11 @@ describe('headers option', () => {
 
     afterAll(testServer.close);
 
-    it('GET request with headers', (done) => {
-      req
+    it('GET request with headers', async () => {
+      await req
         .get('/main')
         .expect('X-Foo', '1')
-        .expect(200, done);
+        .expect(200);
     });
   });
 
@@ -47,17 +47,18 @@ describe('headers option', () => {
 
     afterAll(testServer.close);
 
-    it('GET request with headers as an array', (done) => {
+    it('GET request with headers as an array', async () => {
       // https://github.com/webpack/webpack-dev-server/pull/1650#discussion_r254217027
       const expected = ['v7', 'v8', 'v9'].includes(
         process.version.split('.')[0]
       )
         ? 'key1=value1,key2=value2'
         : 'key1=value1, key2=value2';
-      req
+
+      await req
         .get('/main')
         .expect('X-Bar', expected)
-        .expect(200, done);
+        .expect(200);
     });
   });
 });
diff --git a/test/server/historyApiFallback-option.test.js b/test/server/historyApiFallback-option.test.js
index cc600e7a4a..460e9441fd 100644
--- a/test/server/historyApiFallback-option.test.js
+++ b/test/server/historyApiFallback-option.test.js
@@ -50,11 +50,11 @@ describe('historyApiFallback option', () => {
       req = request(server.app);
     });
 
-    it('request to directory', (done) => {
-      req
+    it('request to directory', async () => {
+      await req
         .get('/foo')
         .accept('html')
-        .expect(200, /Foobar/, done);
+        .expect(200, /Foobar/);
     });
   });
 
@@ -77,18 +77,18 @@ describe('historyApiFallback option', () => {
       req = request(server.app);
     });
 
-    it('historyApiFallback should take preference above directory index', (done) => {
-      req
+    it('historyApiFallback should take preference above directory index', async () => {
+      await req
         .get('/')
         .accept('html')
-        .expect(200, /Foobar/, done);
+        .expect(200, /Foobar/);
     });
 
-    it('request to directory', (done) => {
-      req
+    it('request to directory', async () => {
+      await req
         .get('/foo')
         .accept('html')
-        .expect(200, /Foobar/, done);
+        .expect(200, /Foobar/);
     });
 
     it('contentBase file should take preference above historyApiFallback', (done) => {
@@ -124,11 +124,11 @@ describe('historyApiFallback option', () => {
       req = request(server.app);
     });
 
-    it('historyApiFallback should work and ignore static content', (done) => {
-      req
+    it('historyApiFallback should work and ignore static content', async () => {
+      await req
         .get('/index.html')
         .accept('html')
-        .expect(200, /In-memory file/, done);
+        .expect(200, /In-memory file/);
     });
   });
 
@@ -160,25 +160,25 @@ describe('historyApiFallback option', () => {
       req = request(server.app);
     });
 
-    it('historyApiFallback respect rewrites for index', (done) => {
-      req
+    it('historyApiFallback respect rewrites for index', async () => {
+      await req
         .get('/')
         .accept('html')
-        .expect(200, /Foobar/, done);
+        .expect(200, /Foobar/);
     });
 
-    it('historyApiFallback respect rewrites and shows index for unknown urls', (done) => {
-      req
+    it('historyApiFallback respect rewrites and shows index for unknown urls', async () => {
+      await req
         .get('/acme')
         .accept('html')
-        .expect(200, /Foobar/, done);
+        .expect(200, /Foobar/);
     });
 
-    it('historyApiFallback respect any other specified rewrites', (done) => {
-      req
+    it('historyApiFallback respect any other specified rewrites', async () => {
+      await req
         .get('/other')
         .accept('html')
-        .expect(200, /Other file/, done);
+        .expect(200, /Other file/);
     });
   });
 
@@ -199,11 +199,11 @@ describe('historyApiFallback option', () => {
       req = request(server.app);
     });
 
-    it('should take precedence over contentBase files', (done) => {
-      req
+    it('should take precedence over contentBase files', async () => {
+      await req
         .get('/foo')
         .accept('html')
-        .expect(200, /In-memory file/, done);
+        .expect(200, /In-memory file/);
     });
   });
 });
diff --git a/test/server/host-option.test.js b/test/server/host-option.test.js
index 009379062a..667caabd9f 100644
--- a/test/server/host-option.test.js
+++ b/test/server/host-option.test.js
@@ -50,8 +50,8 @@ describe('host option', () => {
       expect(address.port).toBe(port);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -77,8 +77,8 @@ describe('host option', () => {
       expect(address.port).toBe(port);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -104,8 +104,8 @@ describe('host option', () => {
       expect(address.port).toBe(port);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -131,8 +131,8 @@ describe('host option', () => {
       expect(address.port).toBe(port);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -158,8 +158,8 @@ describe('host option', () => {
       expect(address.port).toBe(port);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
diff --git a/test/server/hot-option.test.js b/test/server/hot-option.test.js
index 979bbad12c..e79679ff4b 100644
--- a/test/server/hot-option.test.js
+++ b/test/server/hot-option.test.js
@@ -26,8 +26,8 @@ describe('hot option', () => {
 
     afterAll(testServer.close);
 
-    it('should include hot script in the bundle', (done) => {
-      req.get('/main.js').expect(200, /webpack\/hot\/dev-server\.js/, done);
+    it('should include hot script in the bundle', async () => {
+      await req.get('/main.js').expect(200, /webpack\/hot\/dev-server\.js/);
     });
   });
 
@@ -51,8 +51,8 @@ describe('hot option', () => {
 
     afterAll(testServer.close);
 
-    it('should include hot script in the bundle', (done) => {
-      req.get('/main.js').expect(200, /webpack\/hot\/dev-server\.js/, done);
+    it('should include hot script in the bundle', async () => {
+      await req.get('/main.js').expect(200, /webpack\/hot\/dev-server\.js/);
     });
   });
 
@@ -72,14 +72,10 @@ describe('hot option', () => {
 
     afterAll(testServer.close);
 
-    it('should NOT include hot script in the bundle', (done) => {
-      req
-        .get('/main.js')
-        .expect(200)
-        .then(({ text }) => {
-          expect(text).not.toMatch(/webpack\/hot\/dev-server\.js/);
-          done();
-        });
+    it('should NOT include hot script in the bundle', async () => {
+      const { text } = await req.get('/main.js').expect(200);
+
+      expect(text).not.toMatch(/webpack\/hot\/dev-server\.js/);
     });
   });
 
diff --git a/test/server/hotOnly-option.test.js b/test/server/hotOnly-option.test.js
index e601325fd3..61cba1eb88 100644
--- a/test/server/hotOnly-option.test.js
+++ b/test/server/hotOnly-option.test.js
@@ -25,10 +25,10 @@ describe('hotOnly options', () => {
 
     afterAll(testServer.close);
 
-    it('should include hotOnly script in the bundle', (done) => {
-      req
+    it('should include hotOnly script in the bundle', async () => {
+      await req
         .get('/main.js')
-        .expect(200, /webpack\/hot\/only-dev-server\.js/, done);
+        .expect(200, /webpack\/hot\/only-dev-server\.js/);
     });
   });
 
diff --git a/test/server/http2-option.test.js b/test/server/http2-option.test.js
index 3e5506558a..eee2862848 100644
--- a/test/server/http2-option.test.js
+++ b/test/server/http2-option.test.js
@@ -109,14 +109,10 @@ describe('http2 option', () => {
       req = request(server.app);
     });
 
-    it('Request to index', (done) => {
-      req
-        .get('/')
-        .expect(200, /Heyo/)
-        .then(({ res }) => {
-          expect(res.httpVersion).not.toEqual('2.0');
-          done();
-        });
+    it('Request to index', async () => {
+      const { res } = await req.get('/').expect(200, /Heyo/);
+
+      expect(res.httpVersion).not.toEqual('2.0');
     });
 
     afterAll(testServer.close);
diff --git a/test/server/https-option.test.js b/test/server/https-option.test.js
index 719875a000..2c569ea5df 100644
--- a/test/server/https-option.test.js
+++ b/test/server/https-option.test.js
@@ -35,8 +35,8 @@ describe('https option', () => {
       req = request(server.app);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, /Heyo/, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200, /Heyo/);
     });
 
     afterAll(() => {
@@ -70,8 +70,8 @@ describe('https option', () => {
       req = request(server.app);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, /Heyo/, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200, /Heyo/);
     });
   });
 
@@ -124,8 +124,8 @@ describe('https option', () => {
       req = request(server.app);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, /Heyo/, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200, /Heyo/);
     });
 
     afterAll(testServer.close);
@@ -160,8 +160,8 @@ describe('https option', () => {
       req = request(server.app);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, /Heyo/, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200, /Heyo/);
     });
   });
 
diff --git a/test/server/inline-option.test.js b/test/server/inline-option.test.js
index 78344621e6..7fc37ad994 100644
--- a/test/server/inline-option.test.js
+++ b/test/server/inline-option.test.js
@@ -26,10 +26,10 @@ describe('inline option', () => {
 
     afterAll(testServer.close);
 
-    it('should include inline client script in the bundle', (done) => {
+    it('should include inline client script in the bundle', async () => {
       const url = new RegExp(`client/index.js\\?http://0.0.0.0:${port}`);
 
-      req.get('/main.js').expect(200, url, done);
+      await req.get('/main.js').expect(200, url);
     });
   });
 
@@ -76,14 +76,10 @@ describe('inline option', () => {
 
     afterAll(testServer.close);
 
-    it('should NOT include inline client script in the bundle', (done) => {
-      req
-        .get('/main.js')
-        .expect(200)
-        .then(({ text }) => {
-          expect(text.includes(`client/index.js?http://0.0.0.0:${port}`));
-          done();
-        });
+    it('should NOT include inline client script in the bundle', async () => {
+      const { text } = await req.get('/main.js').expect(200);
+
+      expect(text.includes(`client/index.js?http://0.0.0.0:${port}`));
     });
   });
 });
diff --git a/test/server/mimeTypes-option.test.js b/test/server/mimeTypes-option.test.js
index 662007dadd..5f2fef5e7a 100644
--- a/test/server/mimeTypes-option.test.js
+++ b/test/server/mimeTypes-option.test.js
@@ -54,11 +54,11 @@ describe('mimeTypes option', () => {
 
     afterAll(testServer.close);
 
-    it('request to bundle file with modified mime type', (done) => {
-      req
+    it('request to bundle file with modified mime type', async () => {
+      await req
         .get('/main.js')
         .expect('Content-Type', /application\/octet-stream/)
-        .expect(200, done);
+        .expect(200);
     });
   });
 });
diff --git a/test/server/open-option.test.js b/test/server/open-option.test.js
index b33d0a834c..6417a97ddd 100644
--- a/test/server/open-option.test.js
+++ b/test/server/open-option.test.js
@@ -1,9 +1,9 @@
 'use strict';
 
-jest.mock('opn');
+jest.mock('open');
 
 const webpack = require('webpack');
-const open = require('opn');
+const open = require('open');
 const Server = require('../../lib/Server');
 const config = require('../fixtures/simple-config/webpack.config');
 const port = require('../ports-map')['open-option'];
diff --git a/test/server/port-option.test.js b/test/server/port-option.test.js
index ff7488de80..d9fd6c2391 100644
--- a/test/server/port-option.test.js
+++ b/test/server/port-option.test.js
@@ -23,8 +23,8 @@ describe('port', () => {
       expect(address.port).toBeDefined();
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -51,8 +51,8 @@ describe('port', () => {
       expect(address.port).toBeDefined();
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -78,8 +78,8 @@ describe('port', () => {
       expect(address.port).toBeDefined();
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -104,8 +104,8 @@ describe('port', () => {
       expect(address.port).toBe(33333);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
@@ -130,8 +130,8 @@ describe('port', () => {
       expect(address.port).toBe(33333);
     });
 
-    it('Request to index', (done) => {
-      req.get('/').expect(200, done);
+    it('Request to index', async () => {
+      await req.get('/').expect(200);
     });
 
     afterAll(testServer.close);
diff --git a/test/server/proxy-option.test.js b/test/server/proxy-option.test.js
index 6f21967248..21917d9ab8 100644
--- a/test/server/proxy-option.test.js
+++ b/test/server/proxy-option.test.js
@@ -108,32 +108,32 @@ describe('proxy option', () => {
     });
 
     describe('target', () => {
-      it('respects a proxy option when a request path is matched', (done) => {
-        req.get('/proxy1').expect(200, 'from proxy1', done);
+      it('respects a proxy option when a request path is matched', async () => {
+        await req.get('/proxy1').expect(200, 'from proxy1');
       });
     });
 
     describe('pathRewrite', () => {
-      it('respects a pathRewrite option', (done) => {
-        req.get('/api/proxy2').expect(200, 'from proxy2', done);
+      it('respects a pathRewrite option', async () => {
+        await req.get('/api/proxy2').expect(200, 'from proxy2');
       });
     });
 
     describe('bypass', () => {
-      it('can rewrite a request path', (done) => {
-        req.get('/foo/bar.html').expect(200, /Hello/, done);
+      it('can rewrite a request path', async () => {
+        await req.get('/foo/bar.html').expect(200, /Hello/);
       });
 
-      it('can rewrite a request path regardless of the target defined a bypass option', (done) => {
-        req.get('/baz/hoge.html').expect(200, /Hello/, done);
+      it('can rewrite a request path regardless of the target defined a bypass option', async () => {
+        await req.get('/baz/hoge.html').expect(200, /Hello/);
       });
 
-      it('should pass through a proxy when a bypass function returns null', (done) => {
-        req.get('/foo.js').expect(200, /Hey/, done);
+      it('should pass through a proxy when a bypass function returns null', async () => {
+        await req.get('/foo.js').expect(200, /Hey/);
       });
 
-      it('should not pass through a proxy when a bypass function returns false', (done) => {
-        req.get('/proxyfalse').expect(404, done);
+      it('should not pass through a proxy when a bypass function returns false', async () => {
+        await req.get('/proxyfalse').expect(404);
       });
     });
   });
@@ -164,8 +164,8 @@ describe('proxy option', () => {
       });
     });
 
-    it('respects a proxy option', (done) => {
-      req.get('/proxy1').expect(200, 'from proxy1', done);
+    it('respects a proxy option', async () => {
+      await req.get('/proxy1').expect(200, 'from proxy1');
     });
   });
 
@@ -195,12 +195,12 @@ describe('proxy option', () => {
       });
     });
 
-    it('respects a proxy option', (done) => {
-      req.get('/proxy1').expect(200, 'from proxy1', done);
+    it('respects a proxy option', async () => {
+      await req.get('/proxy1').expect(200, 'from proxy1');
     });
 
-    it('respects a proxy option of function', (done) => {
-      req.get('/api/proxy2').expect(200, 'from proxy2', done);
+    it('respects a proxy option of function', async () => {
+      await req.get('/api/proxy2').expect(200, 'from proxy2');
     });
   });
 
@@ -243,12 +243,12 @@ describe('proxy option', () => {
       });
     });
 
-    it('respects proxy1 option', (done) => {
-      req.get('/proxy1').expect(200, 'from proxy', done);
+    it('respects proxy1 option', async () => {
+      await req.get('/proxy1').expect(200, 'from proxy');
     });
 
-    it('respects proxy2 option', (done) => {
-      req.get('/proxy2').expect(200, 'from proxy', done);
+    it('respects proxy2 option', async () => {
+      await req.get('/proxy2').expect(200, 'from proxy');
     });
   });
 
@@ -366,36 +366,35 @@ describe('proxy option', () => {
       });
     });
 
-    it('GET method', (done) => {
-      req.get('/get').expect(200, 'GET method from proxy', done);
+    it('GET method', async () => {
+      await req.get('/get').expect(200, 'GET method from proxy');
     });
 
     it('HEAD method', (done) => {
       req.head('/head').expect(200, done);
     });
 
-    it('POST method (application/x-www-form-urlencoded)', (done) => {
-      req
+    it('POST method (application/x-www-form-urlencoded)', async () => {
+      await req
         .post('/post-x-www-form-urlencoded')
         .send('id=1')
-        .expect(200, 'POST method from proxy (id: 1)', done);
+        .expect(200, 'POST method from proxy (id: 1)');
     });
 
-    it('POST method (application/json)', (done) => {
-      req
+    it('POST method (application/json)', async () => {
+      await req
         .post('/post-application-json')
         .send({ id: '1' })
         .set('Accept', 'application/json')
         .expect('Content-Type', /json/)
         .expect(
           200,
-          JSON.stringify({ answer: 'POST method from proxy (id: 1)' }),
-          done
+          JSON.stringify({ answer: 'POST method from proxy (id: 1)' })
         );
     });
 
-    it('DELETE method', (done) => {
-      req.delete('/delete').expect(200, 'DELETE method from proxy', done);
+    it('DELETE method', async () => {
+      await req.delete('/delete').expect(200, 'DELETE method from proxy');
     });
   });
 });
diff --git a/test/server/serverMode-option.test.js b/test/server/serverMode-option.test.js
index b0ef7357fb..1cd89e76da 100644
--- a/test/server/serverMode-option.test.js
+++ b/test/server/serverMode-option.test.js
@@ -34,8 +34,8 @@ describe('serverMode option', () => {
       req = request(`http://localhost:${port}`);
     });
 
-    it('sockjs path responds with a 200', (done) => {
-      req.get('/sockjs-node').expect(200, done);
+    it('sockjs path responds with a 200', async () => {
+      await req.get('/sockjs-node').expect(200);
     });
   });
 
@@ -52,8 +52,8 @@ describe('serverMode option', () => {
       req = request(`http://localhost:${port}`);
     });
 
-    it('sockjs path responds with a 200', (done) => {
-      req.get('/sockjs-node').expect(200, done);
+    it('sockjs path responds with a 200', async () => {
+      await req.get('/sockjs-node').expect(200);
     });
   });
 
@@ -70,8 +70,8 @@ describe('serverMode option', () => {
       req = request(`http://localhost:${port}`);
     });
 
-    it('sockjs path responds with a 200', (done) => {
-      req.get('/sockjs-node').expect(200, done);
+    it('sockjs path responds with a 200', async () => {
+      await req.get('/sockjs-node').expect(200);
     });
   });
 
diff --git a/test/server/servers/SockJSServer.test.js b/test/server/servers/SockJSServer.test.js
index d1024c5910..a099f16e0c 100644
--- a/test/server/servers/SockJSServer.test.js
+++ b/test/server/servers/SockJSServer.test.js
@@ -4,6 +4,7 @@ const http = require('http');
 const express = require('express');
 const SockJS = require('sockjs-client/dist/sockjs');
 const SockJSServer = require('../../../lib/servers/SockJSServer');
+const timer = require('../../helpers/timer');
 const port = require('../../ports-map').SockJSServer;
 
 describe('SockJSServer', () => {
@@ -32,15 +33,16 @@ describe('SockJSServer', () => {
   });
 
   describe('server', () => {
-    it('should recieve connection, send message, and close client', (done) => {
+    it('should recieve connection, send message, and close client', async () => {
       const data = [];
 
-      socketServer.onConnection((connection) => {
+      socketServer.onConnection(async (connection) => {
         data.push('open');
         socketServer.send(connection, 'hello world');
-        setTimeout(() => {
-          socketServer.close(connection);
-        }, 1000);
+
+        await timer(1000);
+
+        socketServer.close(connection);
       });
 
       const client = new SockJS(`http://localhost:${port}/sockjs-node`);
@@ -53,13 +55,12 @@ describe('SockJSServer', () => {
         data.push('close');
       };
 
-      setTimeout(() => {
-        expect(data.length).toEqual(3);
-        expect(data[0]).toEqual('open');
-        expect(data[1]).toEqual('hello world');
-        expect(data[2]).toEqual('close');
-        done();
-      }, 3000);
+      await timer(3000);
+
+      expect(data.length).toEqual(3);
+      expect(data[0]).toEqual('open');
+      expect(data[1]).toEqual('hello world');
+      expect(data[2]).toEqual('close');
     });
   });
 
diff --git a/test/server/sockPath-option.test.js b/test/server/sockPath-option.test.js
index b6840228b5..860e3818be 100644
--- a/test/server/sockPath-option.test.js
+++ b/test/server/sockPath-option.test.js
@@ -25,8 +25,8 @@ describe('sockPath options', () => {
       expect(!!server.sockPath.match(/\/[a-z0-9\-/]+[^/]$/)).toBeTruthy();
     });
 
-    it('responds with a 200', (done) => {
-      req.get('/sockjs-node').expect(200, done);
+    it('responds with a 200', async () => {
+      await req.get('/sockjs-node').expect(200);
     });
   });
 
@@ -49,8 +49,8 @@ describe('sockPath options', () => {
       expect(server.sockPath).toEqual(path);
     });
 
-    it('responds with a 200 second', (done) => {
-      req.get(path).expect(200, done);
+    it('responds with a 200 second', async () => {
+      await req.get(path).expect(200);
     });
   });
 });
diff --git a/test/server/stats-option.test.js b/test/server/stats-option.test.js
index 82d58fd233..45e7cc3035 100644
--- a/test/server/stats-option.test.js
+++ b/test/server/stats-option.test.js
@@ -6,7 +6,7 @@ const config = require('../fixtures/simple-config/webpack.config');
 const port = require('../ports-map')['stats-option'];
 
 describe('stats option', () => {
-  it(`should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors')`, () => {
+  it(`should works with difference stats values (contains 'hash', 'assets', 'warnings' and 'errors')`, async () => {
     const allStats = [
       {},
       // eslint-disable-next-line no-undefined
@@ -18,23 +18,22 @@ describe('stats option', () => {
       },
     ];
 
-    return allStats.reduce((p, stats) => {
-      return p.then(() => {
-        return new Promise((resolve) => {
-          const compiler = webpack(config);
-          const server = new Server(compiler, { stats, port });
+    for (const stats of allStats) {
+      const compiler = webpack(config);
+      const server = new Server(compiler, { stats, port });
 
-          compiler.hooks.done.tap('webpack-dev-server', (s) => {
-            expect(Object.keys(server.getStats(s))).toMatchSnapshot();
+      // eslint-disable-next-line no-await-in-loop
+      await new Promise((resolve) => {
+        compiler.hooks.done.tap('webpack-dev-server', (s) => {
+          expect(Object.keys(server.getStats(s))).toMatchSnapshot();
 
-            server.close(resolve);
-          });
-
-          compiler.run(() => {});
-          server.listen(port, 'localhost');
+          server.close(resolve);
         });
+
+        compiler.run(() => {});
+        server.listen(port, 'localhost');
       });
-    }, Promise.resolve());
+    }
   });
 
   it('should respect warningsFilter', (done) => {
diff --git a/test/server/utils/addEntries.test.js b/test/server/utils/addEntries.test.js
index 608bd61a30..026298e923 100644
--- a/test/server/utils/addEntries.test.js
+++ b/test/server/utils/addEntries.test.js
@@ -17,7 +17,7 @@ describe('addEntries util', () => {
 
     expect(webpackOptions.entry.length).toEqual(2);
     expect(
-      normalize(webpackOptions.entry[0]).indexOf('client/index.js?') !== -1
+      normalize(webpackOptions.entry[0]).includes('client/index.js?')
     ).toBeTruthy();
     expect(normalize(webpackOptions.entry[1])).toEqual('./foo.js');
   });
@@ -33,7 +33,7 @@ describe('addEntries util', () => {
 
     expect(webpackOptions.entry.length).toEqual(3);
     expect(
-      normalize(webpackOptions.entry[0]).indexOf('client/index.js?') !== -1
+      normalize(webpackOptions.entry[0]).includes('client/index.js?')
     ).toBeTruthy();
     expect(webpackOptions.entry[1]).toEqual('./foo.js');
     expect(webpackOptions.entry[2]).toEqual('./bar.js');
@@ -54,7 +54,7 @@ describe('addEntries util', () => {
     expect(webpackOptions.entry.foo.length).toEqual(2);
 
     expect(
-      normalize(webpackOptions.entry.foo[0]).indexOf('client/index.js?') !== -1
+      normalize(webpackOptions.entry.foo[0]).includes('client/index.js?')
     ).toBeTruthy();
     expect(webpackOptions.entry.foo[1]).toEqual('./foo.js');
     expect(webpackOptions.entry.bar[1]).toEqual('./bar.js');
@@ -70,7 +70,7 @@ describe('addEntries util', () => {
     expect(webpackOptions.entry[1]).toEqual('./src');
   });
 
-  it('should preserves dynamic entry points', (done) => {
+  it('should preserves dynamic entry points', async () => {
     let i = 0;
     const webpackOptions = {
       // simulate dynamic entry
@@ -85,22 +85,21 @@ describe('addEntries util', () => {
 
     expect(typeof webpackOptions.entry).toEqual('function');
 
-    webpackOptions
-      .entry()
-      .then((entryFirstRun) =>
-        webpackOptions.entry().then((entrySecondRun) => {
-          expect(entryFirstRun.length).toEqual(2);
-          expect(entryFirstRun[1]).toEqual('./src-1.js');
-
-          expect(entrySecondRun.length).toEqual(2);
-          expect(entrySecondRun[1]).toEqual('./src-2.js');
-          done();
-        })
-      )
-      .catch(done);
+    {
+      const entry = await webpackOptions.entry();
+
+      expect(entry.length).toEqual(2);
+      expect(entry[1]).toEqual('./src-1.js');
+    }
+    {
+      const entry = await webpackOptions.entry();
+
+      expect(entry.length).toEqual(2);
+      expect(entry[1]).toEqual('./src-2.js');
+    }
   });
 
-  it('should preserves asynchronous dynamic entry points', (done) => {
+  it('should preserves asynchronous dynamic entry points', async () => {
     let i = 0;
     const webpackOptions = {
       // simulate async dynamic entry
@@ -117,19 +116,18 @@ describe('addEntries util', () => {
 
     expect(typeof webpackOptions.entry).toEqual('function');
 
-    webpackOptions
-      .entry()
-      .then((entryFirstRun) =>
-        webpackOptions.entry().then((entrySecondRun) => {
-          expect(entryFirstRun.length).toEqual(2);
-          expect(entryFirstRun[1]).toEqual('./src-1.js');
-
-          expect(entrySecondRun.length).toEqual(2);
-          expect(entrySecondRun[1]).toEqual('./src-2.js');
-          done();
-        })
-      )
-      .catch(done);
+    {
+      const entry = await webpackOptions.entry();
+
+      expect(entry.length).toEqual(2);
+      expect(entry[1]).toEqual('./src-1.js');
+    }
+    {
+      const entry = await webpackOptions.entry();
+
+      expect(entry.length).toEqual(2);
+      expect(entry[1]).toEqual('./src-2.js');
+    }
   });
 
   it("should prepends webpack's hot reload client script", () => {
@@ -292,7 +290,7 @@ describe('addEntries util', () => {
 
       if (expectInline) {
         expect(
-          normalize(webpackOptions.entry[0]).indexOf('client/index.js?') !== -1
+          normalize(webpackOptions.entry[0]).includes('client/index.js?')
         ).toBeTruthy();
       }
 
@@ -324,7 +322,7 @@ describe('addEntries util', () => {
 
       if (expectInline) {
         expect(
-          normalize(webpackOptions.entry[0]).indexOf('client/index.js?') !== -1
+          normalize(webpackOptions.entry[0]).includes('client/index.js?')
         ).toBeTruthy();
       }
 
@@ -380,7 +378,7 @@ describe('addEntries util', () => {
     expect(webWebpackOptions.entry.length).toEqual(2);
 
     expect(
-      normalize(webWebpackOptions.entry[0]).indexOf('client/index.js?') !== -1
+      normalize(webWebpackOptions.entry[0]).includes('client/index.js?')
     ).toBeTruthy();
 
     expect(normalize(webWebpackOptions.entry[1])).toEqual('./foo.js');
diff --git a/test/server/utils/findPort.test.js b/test/server/utils/findPort.test.js
index 92ccc36e22..9ab59edd5e 100644
--- a/test/server/utils/findPort.test.js
+++ b/test/server/utils/findPort.test.js
@@ -7,106 +7,109 @@ const findPort = require('../../../lib/utils/findPort');
 describe('findPort util', () => {
   let dummyServers = [];
 
-  afterEach(() => {
+  afterEach(async () => {
     delete process.env.DEFAULT_PORT_RETRY;
 
-    return dummyServers
-      .reduce((p, server) => {
-        return p.then(() => {
-          return new Promise((resolve) => {
-            server.close(resolve);
-          });
-        });
-      }, Promise.resolve())
-      .then(() => {
-        dummyServers = [];
+    async function close(server) {
+      return new Promise((resolve) => {
+        server.close(resolve);
       });
+    }
+
+    for (const server of dummyServers) {
+      // eslint-disable-next-line no-await-in-loop
+      await close(server);
+    }
+
+    dummyServers = [];
   });
 
-  function createDummyServers(n) {
-    return (Array.isArray(n) ? n : [...new Array(n)]).reduce((p, _, i) => {
-      return p.then(() => {
-        return new Promise((resolve) => {
-          const server = http.createServer();
-          dummyServers.push(server);
-          server.listen(8080 + i, resolve);
-        });
+  async function createDummyServers(n) {
+    async function create(i) {
+      return new Promise((resolve) => {
+        const server = http.createServer();
+        dummyServers.push(server);
+        server.listen(8080 + i, resolve);
       });
-    }, Promise.resolve());
+    }
+
+    const samples = [...new Array(n)].map((_, i) => i);
+
+    for (const i of samples) {
+      // eslint-disable-next-line no-await-in-loop
+      await create(i);
+    }
   }
 
-  it('should returns the port when the port is specified', () => {
+  it('should returns the port when the port is specified', async () => {
     process.env.DEFAULT_PORT_RETRY = 5;
 
-    return findPort(8082).then((port) => {
-      expect(port).toEqual(8082);
-    });
+    const port = await findPort(8082);
+    expect(port).toEqual(8082);
   });
 
-  it.only('should returns the port when the port is null', () => {
+  it.only('should returns the port when the port is null', async () => {
     const retryCount = 2;
 
     process.env.DEFAULT_PORT_RETRY = 2;
 
-    return createDummyServers(retryCount)
-      .then(() => findPort(null))
-      .then((port) => {
-        expect(port).toEqual(8080 + retryCount);
-      });
+    await createDummyServers(retryCount);
+
+    const port = await findPort(null);
+
+    expect(port).toEqual(8080 + retryCount);
   });
 
-  it('should returns the port when the port is undefined', () => {
+  it('should returns the port when the port is undefined', async () => {
     const retryCount = 2;
 
     process.env.DEFAULT_PORT_RETRY = 2;
 
-    return (
-      createDummyServers(retryCount)
-        // eslint-disable-next-line no-undefined
-        .then(() => findPort(undefined))
-        .then((port) => {
-          expect(port).toEqual(8080 + retryCount);
-        })
-    );
+    await createDummyServers(retryCount);
+
+    // eslint-disable-next-line no-undefined
+    const port = findPort(undefined);
+
+    expect(port).toEqual(8080 + retryCount);
   });
 
-  it('should retry finding the port for up to defaultPortRetry times (number)', () => {
+  it('should retry finding the port for up to defaultPortRetry times (number)', async () => {
     const retryCount = 3;
 
     process.env.DEFAULT_PORT_RETRY = retryCount;
 
-    return createDummyServers(retryCount)
-      .then(() => findPort())
-      .then((port) => {
-        expect(port).toEqual(8080 + retryCount);
-      });
+    await createDummyServers(retryCount);
+
+    const port = await findPort();
+
+    expect(port).toEqual(8080 + retryCount);
   });
 
-  it('should retry finding the port for up to defaultPortRetry times (string)', () => {
+  it('should retry finding the port for up to defaultPortRetry times (string)', async () => {
     const retryCount = 3;
 
     process.env.DEFAULT_PORT_RETRY = `${retryCount}`;
 
-    return createDummyServers(retryCount)
-      .then(() => findPort())
-      .then((port) => {
-        expect(port).toEqual(8080 + retryCount);
-      });
+    await createDummyServers(retryCount);
+
+    const port = await findPort();
+
+    expect(port).toEqual(8080 + retryCount);
   });
 
-  it('should retry finding the port when serial ports are busy', () => {
+  it('should retry finding the port when serial ports are busy', async () => {
     const busyPorts = [8080, 8081, 8082, 8083];
 
     process.env.DEFAULT_PORT_RETRY = 3;
 
-    return createDummyServers(busyPorts)
-      .then(() => findPort())
-      .then((port) => {
-        expect(port).toEqual(8080 + busyPorts.length);
-      });
+    await createDummyServers(busyPorts);
+
+    const port = await findPort();
+
+    expect(port).toEqual(8080 + busyPorts.length);
   });
 
-  it("should throws the error when the port isn't found", () => {
+  it("should throws the error when the port isn't found", async () => {
     expect.assertions(1);
 
     const spy = jest
@@ -119,12 +122,14 @@ describe('findPort util', () => {
 
     process.env.DEFAULT_PORT_RETRY = 0;
 
-    return createDummyServers(retryCount)
-      .then(() => findPort())
-      .catch((err) => {
-        expect(err.message).toMatchSnapshot();
+    await createDummyServers(retryCount);
 
-        spy.mockRestore();
-      });
+    try {
+      await findPort();
+    } catch (err) {
+      expect(err.message).toMatchSnapshot();
+    }
+
+    spy.mockRestore();
   });
 });
diff --git a/test/server/utils/routes.test.js b/test/server/utils/routes.test.js
index c5f0d7369e..27115a9d4b 100644
--- a/test/server/utils/routes.test.js
+++ b/test/server/utils/routes.test.js
@@ -16,111 +16,105 @@ describe('routes util', () => {
 
   afterAll(testServer.close);
 
-  it('should handles GET request to live bundle', (done) => {
-    req.get('/__webpack_dev_server__/live.bundle.js').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('application/javascript');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to live bundle', async () => {
+    const { headers, statusCode } = await req.get(
+      '/__webpack_dev_server__/live.bundle.js'
+    );
+
+    expect(headers['content-type']).toEqual('application/javascript');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to live bundle', (done) => {
-    req.head('/__webpack_dev_server__/live.bundle.js').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('application/javascript');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to live bundle', async () => {
+    const { headers, statusCode } = await req.head(
+      '/__webpack_dev_server__/live.bundle.js'
+    );
+
+    expect(headers['content-type']).toEqual('application/javascript');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles GET request to sockjs bundle', (done) => {
-    req.get('/__webpack_dev_server__/sockjs.bundle.js').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('application/javascript');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to sockjs bundle', async () => {
+    const { headers, statusCode } = await req.get(
+      '/__webpack_dev_server__/sockjs.bundle.js'
+    );
+
+    expect(headers['content-type']).toEqual('application/javascript');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to sockjs bundle', (done) => {
-    req.head('/__webpack_dev_server__/sockjs.bundle.js').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('application/javascript');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to sockjs bundle', async () => {
+    const { headers, statusCode } = await req.head(
+      '/__webpack_dev_server__/sockjs.bundle.js'
+    );
+
+    expect(headers['content-type']).toEqual('application/javascript');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles GET request to inline bundle', (done) => {
-    req.get('/webpack-dev-server.js').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('application/javascript');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to inline bundle', async () => {
+    const { headers, statusCode } = await req.get('/webpack-dev-server.js');
+
+    expect(headers['content-type']).toEqual('application/javascript');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to inline bundle', (done) => {
-    req.head('/webpack-dev-server.js').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('application/javascript');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to inline bundle', async () => {
+    const { headers, statusCode } = await req.head('/webpack-dev-server.js');
+
+    expect(headers['content-type']).toEqual('application/javascript');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles GET request to live html', (done) => {
-    req.get('/webpack-dev-server/').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('text/html');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to live html', async () => {
+    const { headers, statusCode } = await req.get('/webpack-dev-server/');
+
+    expect(headers['content-type']).toEqual('text/html');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to live html', (done) => {
-    req.head('/webpack-dev-server/').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('text/html');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to live html', async () => {
+    const { headers, statusCode } = await req.head('/webpack-dev-server/');
+
+    expect(headers['content-type']).toEqual('text/html');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles GET request to directory index', (done) => {
-    req.get('/webpack-dev-server').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('text/html');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to directory index', async () => {
+    const { headers, statusCode } = await req.get('/webpack-dev-server');
+
+    expect(headers['content-type']).toEqual('text/html');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to directory index', (done) => {
-    req.head('/webpack-dev-server').then(({ res }) => {
-      expect(res.headers['content-type']).toEqual('text/html');
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to directory index', async () => {
+    const { headers, statusCode } = await req.head('/webpack-dev-server');
+
+    expect(headers['content-type']).toEqual('text/html');
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles GET request to magic html', (done) => {
-    req.get('/main').then(({ res }) => {
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to magic html', async () => {
+    const { statusCode } = await req.get('/main');
+
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to magic html', (done) => {
-    req.head('/main').then(({ res }) => {
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to magic html', async () => {
+    const { statusCode } = await req.head('/main');
+
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles GET request to main chunk', (done) => {
-    req.get('/main.js').then(({ res }) => {
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles GET request to main chunk', async () => {
+    const { statusCode } = await req.get('/main.js');
+
+    expect(statusCode).toEqual(200);
   });
 
-  it('should handles HEAD request to main chunk', (done) => {
-    req.head('/main.js').then(({ res }) => {
-      expect(res.statusCode).toEqual(200);
-      done();
-    });
+  it('should handles HEAD request to main chunk', async () => {
+    const { statusCode } = await req.head('/main.js');
+
+    expect(statusCode).toEqual(200);
   });
 });
diff --git a/test/server/utils/runOpen.test.js b/test/server/utils/runOpen.test.js
index e6fa3b155a..1ae6b092d1 100644
--- a/test/server/utils/runOpen.test.js
+++ b/test/server/utils/runOpen.test.js
@@ -1,23 +1,24 @@
 'use strict';
 
-const opn = require('opn');
+const open = require('open');
 const runOpen = require('../../../lib/utils/runOpen');
 
-jest.mock('opn');
+jest.mock('open');
 
 describe('runOpen util', () => {
   afterEach(() => {
-    opn.mockClear();
+    open.mockClear();
   });
 
   describe('should open browser', () => {
     beforeEach(() => {
-      opn.mockImplementation(() => Promise.resolve());
+      open.mockImplementation(() => Promise.resolve());
     });
 
-    it('on specify URL', () => {
-      return runOpen('https://example.com', {}, console).then(() => {
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+    it('on specify URL', async () => {
+      await runOpen('https://example.com', {}, console);
+
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com",
             Object {
@@ -25,16 +26,16 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
 
-    it('on specify URL with page', () => {
-      return runOpen(
+    it('on specify URL with page', async () => {
+      await runOpen(
         'https://example.com',
         { openPage: '/index.html' },
         console
-      ).then(() => {
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+      );
+
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com/index.html",
             Object {
@@ -42,16 +43,12 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
 
-    it('on specify URL in Google Chrome', () => {
-      return runOpen(
-        'https://example.com',
-        { open: 'Google Chrome' },
-        console
-      ).then(() => {
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+    it('on specify URL in Google Chrome', async () => {
+      await runOpen('https://example.com', { open: 'Google Chrome' }, console);
+
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com",
             Object {
@@ -60,16 +57,16 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
 
-    it('on specify URL with page in Google Chrome ', () => {
-      return runOpen(
+    it('on specify URL with page in Google Chrome ', async () => {
+      await runOpen(
         'https://example.com',
         { open: 'Google Chrome', openPage: '/index.html' },
         console
-      ).then(() => {
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+      );
+
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com/index.html",
             Object {
@@ -78,16 +75,17 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
+  });
 
-    it('on specify absolute https URL with page in Google Chrome ', () => {
-      return runOpen(
-        'https://example.com',
-        { open: 'Google Chrome', openPage: 'https://example2.com' },
-        console
-      ).then(() => {
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+  it('on specify absolute https URL with page in Google Chrome ', async () => {
+    await runOpen(
+      'https://example.com',
+      { open: 'Google Chrome', openPage: 'https://example2.com' },
+      console
+    );
+
+    expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example2.com",
             Object {
@@ -96,16 +94,16 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
-    });
+  });
 
-    it('on specify absolute http URL with page in Google Chrome ', () => {
-      return runOpen(
-        'https://example.com',
-        { open: 'Google Chrome', openPage: 'http://example2.com' },
-        console
-      ).then(() => {
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+  it('on specify absolute http URL with page in Google Chrome ', async () => {
+    runOpen(
+      'https://example.com',
+      { open: 'Google Chrome', openPage: 'http://example2.com' },
+      console
+    );
+
+    expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "http://example2.com",
             Object {
@@ -114,27 +112,26 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
-    });
   });
 
   describe('should not open browser', () => {
     const logMock = { warn: jest.fn() };
 
     beforeEach(() => {
-      opn.mockImplementation(() => Promise.reject());
+      open.mockImplementation(() => Promise.reject());
     });
 
     afterEach(() => {
       logMock.warn.mockClear();
     });
 
-    it('on specify URL and log error', () => {
-      return runOpen('https://example.com', {}, logMock).then(() => {
-        expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
-          `"Unable to open browser. If you are running in a headless environment, please do not use the --open flag"`
-        );
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+    it('on specify URL and log error', async () => {
+      await runOpen('https://example.com', {}, logMock);
+
+      expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
+        `"Unable to open browser. If you are running in a headless environment, please do not use the --open flag"`
+      );
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com",
             Object {
@@ -142,19 +139,19 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
 
-    it('on specify URL with page and log error', () => {
-      return runOpen(
+    it('on specify URL with page and log error', async () => {
+      await runOpen(
         'https://example.com',
         { openPage: '/index.html' },
         logMock
-      ).then(() => {
-        expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
-          `"Unable to open browser. If you are running in a headless environment, please do not use the --open flag"`
-        );
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+      );
+
+      expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
+        `"Unable to open browser. If you are running in a headless environment, please do not use the --open flag"`
+      );
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com/index.html",
             Object {
@@ -162,19 +159,15 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
 
-    it('on specify URL in Google Chrome and log error', () => {
-      return runOpen(
-        'https://example.com',
-        { open: 'Google Chrome' },
-        logMock
-      ).then(() => {
-        expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
-          `"Unable to open browser: Google Chrome. If you are running in a headless environment, please do not use the --open flag"`
-        );
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+    it('on specify URL in Google Chrome and log error', async () => {
+      await runOpen('https://example.com', { open: 'Google Chrome' }, logMock);
+
+      expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
+        `"Unable to open browser: Google Chrome. If you are running in a headless environment, please do not use the --open flag"`
+      );
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com",
             Object {
@@ -183,19 +176,19 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
 
-    it('on specify URL with page in Google Chrome and log error ', () => {
-      return runOpen(
+    it('on specify URL with page in Google Chrome and log error ', async () => {
+      await runOpen(
         'https://example.com',
         { open: 'Google Chrome', openPage: '/index.html' },
         logMock
-      ).then(() => {
-        expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
-          `"Unable to open browser: Google Chrome. If you are running in a headless environment, please do not use the --open flag"`
-        );
-        expect(opn.mock.calls[0]).toMatchInlineSnapshot(`
+      );
+
+      expect(logMock.warn.mock.calls[0][0]).toMatchInlineSnapshot(
+        `"Unable to open browser: Google Chrome. If you are running in a headless environment, please do not use the --open flag"`
+      );
+      expect(open.mock.calls[0]).toMatchInlineSnapshot(`
           Array [
             "https://example.com/index.html",
             Object {
@@ -204,7 +197,6 @@ describe('runOpen util', () => {
             },
           ]
         `);
-      });
     });
   });
 });