From b7c89658a034a42c7893a65157ce2959eaef74a2 Mon Sep 17 00:00:00 2001
From: Josh Goldberg <josh@fullscreenmario.com>
Date: Tue, 17 Oct 2017 11:15:05 -0700
Subject: [PATCH] Async-ified linterTests.ts

---
 src/utils.ts        | 26 ++++++++++++++++++++++++++
 test/linterTests.ts | 16 +++++++++++-----
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/utils.ts b/src/utils.ts
index 65ef068a3df..98d4db04b89 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -15,6 +15,8 @@
  * limitations under the License.
  */
 
+import * as fs from "fs";
+
 /**
  * Enforces the invariant that the input is an array.
  */
@@ -213,3 +215,27 @@ export function detectBufferEncoding(buffer: Buffer, length = buffer.length): En
 export function denormalizeWinPath(path: string): string {
     return path.replace(/\\/g, "/");
 }
+
+export async function readFileAsync(fileName: string, encoding: string): Promise<string> {
+    return await new Promise<string>((resolve, reject) => {
+        fs.readFile(fileName, encoding, (error: Error | null, contents: string) => {
+            if (error !== null) {
+                reject(error);
+            } else {
+                resolve(contents);
+            }
+        });
+    });
+}
+
+export async function writeFileAsync(fileName: string, data: string): Promise<void> {
+    await new Promise<void>((resolve, reject) => {
+        fs.writeFile(fileName, data, (error?: Error) => {
+            if (error !== null) {
+                reject(error);
+            } else {
+                resolve();
+            }
+        });
+    });
+}
diff --git a/test/linterTests.ts b/test/linterTests.ts
index d35fa4b2421..5c8edfc500c 100644
--- a/test/linterTests.ts
+++ b/test/linterTests.ts
@@ -16,9 +16,9 @@
  */
 
 import { assert } from "chai";
-import * as fs from "fs";
 import { createSourceFile, ScriptTarget } from "typescript";
 import { Replacement, RuleFailure } from "../src/language/rule/rule";
+import { readFileAsync, writeFileAsync } from "../src/utils";
 import { createTempFile } from "./utils";
 
 import Linter = require("../src/linter");
@@ -51,17 +51,23 @@ const templateDeclarationFixed =
 
 describe("Linter", () => {
 
-    it("apply fixes to correct files", () => {
+    it("apply fixes to correct files", async () => {
         const linter = new TestLinter({ fix: true });
         const componentFile = createTempFile("ts");
         const templateFile = createTempFile("ts");
-        fs.writeFileSync(componentFile, componentDeclaration(templateFile));
-        fs.writeFileSync(templateFile, templateDeclaration);
+
+        await Promise.all([
+            writeFileAsync(componentFile, componentDeclaration(templateFile)),
+            writeFileAsync(templateFile, templateDeclaration),
+        ]);
+
         const sourceFile = createSourceFile(templateFile, `${templateDeclaration}`, ScriptTarget.ES2015);
         const replacement = new Replacement(6, 9, "");
         const failure = new RuleFailure(sourceFile, 6, 15, "Declaration doesn't exist", "foo-bar", replacement);
         linter.applyFixesHelper(componentFile, componentDeclaration(templateFile), [failure]);
-        assert.equal(fs.readFileSync(templateFile, "utf-8"), templateDeclarationFixed);
+
+        const actualTemplateFileContents = await readFileAsync(templateFile, "utf-8");
+        assert.equal(actualTemplateFileContents, templateDeclarationFixed);
     });
 
 });