diff --git a/.eslintignore b/.eslintignore
new file mode 100644
index 0000000..59d90e7
--- /dev/null
+++ b/.eslintignore
@@ -0,0 +1,4 @@
+test/fixtures
+logs
+run
+coverage
diff --git a/.eslintrc b/.eslintrc
new file mode 100644
index 0000000..c799fe5
--- /dev/null
+++ b/.eslintrc
@@ -0,0 +1,3 @@
+{
+  "extends": "eslint-config-egg"
+}
diff --git a/.jshintignore b/.jshintignore
deleted file mode 100644
index 9d1cf03..0000000
--- a/.jshintignore
+++ /dev/null
@@ -1,4 +0,0 @@
-.git/
-node_modules/
-coverage/
-docs/
diff --git a/.jshintrc b/.jshintrc
deleted file mode 100644
index 649e9bf..0000000
--- a/.jshintrc
+++ /dev/null
@@ -1,33 +0,0 @@
-{
-  "indent": 2,
-  "latedef": "nofunc",
-  "newcap": true,
-  "curly": true,
-  "eqeqeq": true,
-  "eqnull": true,
-  "strict": true,
-  "undef": true,
-  "unused": true,
-  "laxcomma": false,
-  "asi": false,
-  "boss": false,
-  "expr": true,
-  "sub": true,
-  "quotmark": "single",
-  "loopfunc": false,
-  "lastsemic": true,
-  "funcscope": false,
-  "esnext": true,
-  "noyield": true,
-  "browser": true,
-  "nonstandard": true,
-  "devel": true,
-  "node": true,
-  "mocha": true,
-  "validthis": true,
-  "globals": {
-    "define": false
-  }
-}
-
-
diff --git a/.travis.yml b/.travis.yml
index a614bf7..5ec1467 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,12 @@
+sudo: false
 language: node_js
 node_js:
-  - "4"
-  - "5"
-  - "6"
-sudo: false
-script: make travis
-after_script: "npm install coveralls@2 && cat ./coverage/lcov.info | coveralls"
+  - '4'
+  - '6'
+  - '7'
+install:
+  - npm i npminstall && npminstall
+script:
+  - npm run ci
+after_script:
+  - npminstall codecov && codecov
diff --git a/Makefile b/Makefile
deleted file mode 100644
index da2dd7a..0000000
--- a/Makefile
+++ /dev/null
@@ -1,28 +0,0 @@
-git_version = $$(git branch 2>/dev/null | sed -e '/^[^*]/d'-e's/* \(.*\)/\1/')
-npm_bin= $$(npm bin)
-
-all: test
-install:
-	@npm install
-server:
-	npm i startserver --save-dev
-	${npm_bin}/startserver -s -p 8080 &
-pre-test: server
-	sleep 5
-test:
-	@node \
-		${npm_bin}/istanbul cover ${npm_bin}/_mocha \
-		-- \
-		--timeout 10000 \
-		--require co-mocha
-travis: install pre-test
-	@node \
-		${npm_bin}/istanbul cover ${npm_bin}/_mocha \
-		--report lcovonly \
-		-- -u exports \
-		--timeout 10000 \
-		--require co-mocha \
-		--bail
-jshint:
-	@${npm_bin}/jshint .
-.PHONY: test
diff --git a/README.md b/README.md
index 408a311..c701931 100644
--- a/README.md
+++ b/README.md
@@ -3,9 +3,8 @@
 ---
 
 [![NPM version][npm-image]][npm-url]
-[![node version][node-image]][node-url]
 [![build status][travis-image]][travis-url]
-[![Coveralls][coveralls-image]][coveralls-url]
+[![Test coverage][codecov-image]][codecov-url]
 [![npm download][download-image]][download-url]
 
 [logo-image]: ./logo.png
@@ -14,10 +13,8 @@
 [npm-url]: https://npmjs.org/package/detect-port
 [travis-image]: https://img.shields.io/travis/node-modules/detect-port.svg?style=flat-square
 [travis-url]: https://travis-ci.org/node-modules/detect-port
-[coveralls-image]: https://img.shields.io/coveralls/node-modules/detect-port.svg?style=flat-square
-[coveralls-url]: https://coveralls.io/r/node-modules/detect-port?branch=master
-[node-image]: https://img.shields.io/badge/node.js-%3E=_4-red.svg?style=flat-square
-[node-url]: http://nodejs.org/download/
+[codecov-image]: https://codecov.io/gh/node-modules/detect-port/branch/master/graph/badge.svg
+[codecov-url]: https://codecov.io/gh/node-modules/detect-port
 [download-image]: https://img.shields.io/npm/dm/detect-port.svg?style=flat-square
 [download-url]: https://npmjs.org/package/detect-port
 
@@ -25,11 +22,11 @@
 
 ## Usage
 
-```shell
+```bash
 $ npm i detect-port --save
 ```
 
-```javascript
+```js
 const detect = require('detect-port');
 
 /**
diff --git a/appveyor.yml b/appveyor.yml
new file mode 100644
index 0000000..2efd0fa
--- /dev/null
+++ b/appveyor.yml
@@ -0,0 +1,16 @@
+environment:
+  matrix:
+    - nodejs_version: '4'
+    - nodejs_version: '6'
+    - nodejs_version: '7'
+
+install:
+  - ps: Install-Product node $env:nodejs_version
+  - npm i npminstall && node_modules\.bin\npminstall
+
+test_script:
+  - node --version
+  - npm --version
+  - npm run ci
+
+build: off
diff --git a/lib/detect-port.js b/lib/detect-port.js
index 6dff69d..c1cb636 100644
--- a/lib/detect-port.js
+++ b/lib/detect-port.js
@@ -1,73 +1,39 @@
 'use strict';
 
+const debug = require('debug')('detect-port');
 const net = require('net');
 
-module.exports = function() {
-  const args = Array.prototype.slice.call(arguments);
-
-  const promise = new Promise((resolve, reject) => {
-    if (!args.length) {
-      return reject('wrong number of arguments');
-    }
-
-    const port = parseInt(args[0], 10);
-
-    if (isNaN(port)) {
-      return reject(`wrong type of arguments with: '${args[0]}'`);
-    }
-
-    const loop = port => {
-      const socket = new net.Socket();
-
-      socket.once('error', () => {
-        socket.removeAllListeners('error');
-        socket.removeAllListeners('connect');
-        socket.end();
-        socket.destroy();
-        socket.unref();
-
-        const server = new net.Server();
-
-        server.on('error', () => {
-          port++;
-          loop(port);
-        });
-
-        server.listen(port, () => {
-          server.once('close', () => {
-            resolve(port);
-          });
-          server.close();
-        });
-      });
-
-      socket.once('connect', () => {
-        port++;
-        loop(port);
-        socket.removeAllListeners('error');
-        socket.removeAllListeners('connect');
-        socket.end();
-        socket.destroy();
-        socket.unref();
-      });
+module.exports = (port, callback) => {
+  if (typeof port === 'function') {
+    callback = port;
+    port = null;
+  }
+  if (typeof callback === 'function') {
+    return tryListen(port, callback);
+  }
+  // promise
+  return new Promise(resolve => {
+    tryListen(port, (_, realPort) => {
+      resolve(realPort);
+    });
+  });
+};
 
-      socket.connect({
-        port: port
-      });
-    };
+function tryListen(port, callback) {
+  port = parseInt(port) || 0;
+  const server = new net.Server();
 
-    loop(port);
+  server.on('error', err => {
+    debug('listen %s error: %s', port, err);
+    port = 0;
+    server.close();
+    return tryListen(port, callback);
   });
 
-  if (args.length > 1) {
-    const cb = args[1];
-
-    promise.then(data => {
-      process.nextTick(cb.bind(null, null, data));
-    }, err => {
-      process.nextTick(cb.bind(null, err));
-    });
-  } else {
-    return promise;
-  }
-};
+  server.listen({ port }, () => {
+    port = server.address().port;
+    server.close();
+    debug('get free port: %s', port);
+    callback(null, port);
+  });
+}
diff --git a/package.json b/package.json
index cc8e59a..b70214b 100644
--- a/package.json
+++ b/package.json
@@ -15,26 +15,27 @@
     "type": "git",
     "url": "git://github.com/node-modules/detect-port.git"
   },
-  "dependencies": {},
+  "dependencies": {
+    "debug": "^2.6.0"
+  },
   "devDependencies": {
-    "co-mocha": "*",
     "command-line-test": "^1.0.8",
-    "istanbul": "*",
-    "jshint": "*",
-    "mocha": "2.2.4",
-    "pre-commit": "^1.1.3",
-    "should": "~6.0.3"
+    "egg-bin": "^2.0.0",
+    "egg-ci": "^1.1.0",
+    "eslint": "^3.13.1",
+    "eslint-config-egg": "^3.1.0"
   },
   "scripts": {
-    "test": "make test",
-    "jshint": "make jshint"
+    "test": "egg-bin test",
+    "ci": "npm run lint && egg-bin cov",
+    "lint": "eslint ."
   },
-  "precommit": [
-    "jshint"
-  ],
   "engines": {
     "node": ">= 4.2.1"
   },
+  "ci": {
+    "version": "4, 6, 7"
+  },
   "homepage": "https://github.com/node-modules/detect-port",
   "license": "MIT"
 }
diff --git a/test/cli.test.js b/test/cli.test.js
index aad2494..9aec89d 100644
--- a/test/cli.test.js
+++ b/test/cli.test.js
@@ -2,7 +2,7 @@
 
 const path = require('path');
 const CliTest = require('command-line-test');
-
+const assert = require('assert');
 const pkg = require('../package');
 
 const cliTest = new CliTest();
@@ -10,35 +10,35 @@ const binFile = path.resolve(pkg.bin[pkg.name]);
 
 describe('command-line tool test', () => {
 
-  it('should show version and exit', function *() {
-    var res = yield cliTest.execFile(binFile, ['-v'], {});
-    res.stdout.should.equal(pkg.version);
-    res = yield cliTest.execFile(binFile, ['--version'], {});
-    res.stdout.should.containEql(pkg.version);
+  it('should show version and exit', function* () {
+    let res = yield cliTest.execFile(binFile, [ '-v' ], {});
+    assert(res.stdout === pkg.version);
+    res = yield cliTest.execFile(binFile, [ '--version' ], {});
+    assert(res.stdout.includes(pkg.version));
   });
 
-  it('should output usage information', function *() {
-    var res = yield cliTest.execFile(binFile, ['-h'], {});
-    res.stdout.should.containEql(pkg.description);
-    res = yield cliTest.execFile(binFile, ['--help'], {});
-    res.stdout.should.containEql(pkg.description);
-    res = yield cliTest.execFile(binFile, ['help'], {});
-    res.stdout.should.containEql(pkg.description);
-    res = yield cliTest.execFile(binFile, ['xxx'], {});
-    res.stdout.should.containEql(pkg.description);
+  it('should output usage information', function* () {
+    let res = yield cliTest.execFile(binFile, [ '-h' ], {});
+    assert(res.stdout.includes(pkg.description));
+    res = yield cliTest.execFile(binFile, [ '--help' ], {});
+    assert(res.stdout.includes(pkg.description));
+    res = yield cliTest.execFile(binFile, [ 'help' ], {});
+    assert(res.stdout.includes(pkg.description));
+    res = yield cliTest.execFile(binFile, [ 'xxx' ], {});
+    assert(res.stdout.includes(pkg.description));
   });
 
-  it('should output available port randomly', function *() {
+  it('should output available port randomly', function* () {
     const res = yield cliTest.execFile(binFile, [], {});
     const port = parseInt(res.stdout.split(' ')[3], 10);
-    port.should.within(9000, 65535);
+    assert(port >= 9000 && port < 65535);
   });
 
-  it('should output available port from the given port', function *() {
+  it('should output available port from the given port', function* () {
     const givenPort = 9000;
-    const res = yield cliTest.execFile(binFile, [givenPort], {});
+    const res = yield cliTest.execFile(binFile, [ givenPort ], {});
     const port = parseInt(res.stdout.split(' ')[3], 10);
-    port.should.within(givenPort, 65535);
+    assert(port >= givenPort && port < 65535);
   });
 
 });
diff --git a/test/detect-port.test.js b/test/detect-port.test.js
index 57b4142..fada974 100644
--- a/test/detect-port.test.js
+++ b/test/detect-port.test.js
@@ -1,78 +1,86 @@
 'use strict';
 
+const assert = require('assert');
+const net = require('net');
 const detectPort = require('..');
 
 describe('detect port test', () => {
+  let server;
+  before(done => {
+    server = new net.Server();
+    server.listen(7001, done);
+  });
+  after(() => {
+    server.close();
+  });
+
+  it('get random port', done => {
+    detectPort((_, port) => {
+      assert(port >= 1024 && port < 65535);
+      done();
+    });
+  });
 
   it('callback with occupied port', done => {
     const _port = 80;
-    detectPort(_port, (err, port) => {
-      if (err) {
-        console.log(err);
-      }
-      port.should.within(_port, 65535);
+    detectPort(_port, (_, port) => {
+      assert(port >= _port && port < 65535);
+      done();
+    });
+  });
+
+  it('work with listening port', done => {
+    const port = 7001;
+    detectPort(port, (_, realPort) => {
+      assert(realPort !== 7001);
+      assert(realPort > 0);
       done();
     });
   });
 
   it('callback with string arg', done => {
     const _port = '8080';
-    detectPort(_port, (err, port) => {
-      if (err) {
-        console.log(err);
-      }
-      port.should.within(parseInt(_port, 10), 65535);
+    detectPort(_port, (_, port) => {
+      assert(port >= 8080 && port < 65535);
       done();
     });
   });
 
   it('callback with wrong arguments', done => {
-    detectPort('oooo', err => {
-      err.should.containEql('wrong type of arguments');
+    detectPort('oooo', (_, port) => {
+      assert(port > 0);
       done();
     });
   });
 
-  it('generator usage', function *() {
+  it('generator usage', function* () {
     const _port = 8080;
-    try {
-      const port = yield detectPort(_port);
-      port.should.within(_port, 65535);
-    } catch (err) {
-      console.log(err);
-    }
+    const port = yield detectPort(_port);
+    assert(port >= _port && port < 65535);
   });
 
   it('promise usage', done => {
     const _port = 8080;
     detectPort(_port)
       .then(port => {
-        port.should.within(_port, 65535);
+        assert(port >= _port && port < 65535);
         done();
       })
-      .catch(err => {
-        console.log(err);
-        done();
-      });
+      .catch(done);
   });
 
   it('promise with wrong arguments', done => {
     detectPort()
-      .then(() => {
+      .then(port => {
+        assert(port > 0);
         done();
       })
-      .catch(err => {
-        err.should.containEql('wrong number of arguments');
-        done();
-      });
+      .catch(done);
   });
 
-  it('generator with wrong arguments', function *() {
-    try {
-      yield detectPort('oooo');
-    } catch (err) {
-      err.should.containEql('wrong type of arguments');
-    }
+  it('generator with wrong arguments and return random port', function* () {
+    const port = yield detectPort('oooo');
+    assert(port > 0);
+    assert(typeof port === 'number');
   });
-
 });
diff --git a/test/mocha.opts b/test/mocha.opts
deleted file mode 100644
index 9c3fba0..0000000
--- a/test/mocha.opts
+++ /dev/null
@@ -1,2 +0,0 @@
---require should
---reporter spec