From 759b28080a20fbdf98c6ae52c44d6ca082e8f3c3 Mon Sep 17 00:00:00 2001
From: Jack Franklin <jacktfranklin@chromium.org>
Date: Thu, 18 Jun 2020 16:26:30 +0100
Subject: [PATCH] chore: upgrade to Mocha v8 (#5997)

* chore: upgrade to Mocha v8

Mocha v8 has some nice improvements and also unlocks the potential
to have parallel test runs which may speed up CI.
---
 mocha-config/puppeteer-unit-tests.js |  5 ++-
 package.json                         |  2 +-
 test/coverage-utils.js               | 21 ++++-----
 test/mocha-utils.js                  | 65 +++++++++++++++++-----------
 4 files changed, 55 insertions(+), 38 deletions(-)

diff --git a/mocha-config/puppeteer-unit-tests.js b/mocha-config/puppeteer-unit-tests.js
index 01dcd44e..23fb4f8c 100644
--- a/mocha-config/puppeteer-unit-tests.js
+++ b/mocha-config/puppeteer-unit-tests.js
@@ -18,9 +18,10 @@ const base = require('./base');
 
 module.exports = {
   ...base,
-  file: ['./test/mocha-utils.js'],
+  require: ['./test/mocha-utils.js'],
   spec: 'test/*.spec.js',
+  parallel: process.env.CI && !process.env.COVERAGE,
   // retry twice more, so we run each test up to 3 times if needed.
-  retries: 2,
+  retries: process.env.CI ? 2 : 0,
   timeout: 25 * 1000,
 };
diff --git a/package.json b/package.json
index 0384659e..abfac2c8 100644
--- a/package.json
+++ b/package.json
@@ -84,7 +84,7 @@
     "expect": "^25.2.7",
     "jpeg-js": "^0.3.7",
     "minimist": "^1.2.0",
-    "mocha": "^7.1.1",
+    "mocha": "^8.0.1",
     "ncp": "^2.0.0",
     "pixelmatch": "^4.0.2",
     "pngjs": "^5.0.0",
diff --git a/test/coverage-utils.js b/test/coverage-utils.js
index cff80d7e..cd490e9f 100644
--- a/test/coverage-utils.js
+++ b/test/coverage-utils.js
@@ -102,16 +102,17 @@ const trackCoverage = () => {
   clearOldCoverage();
   const coverageMap = new Map();
 
-  before(() => {
-    const api = require('../lib/api');
-    const events = require('../lib/common/Events');
-    for (const [className, classType] of Object.entries(api))
-      traceAPICoverage(coverageMap, events, className, classType);
-  });
-
-  after(() => {
-    writeCoverage(coverageMap);
-  });
+  return {
+    beforeAll: () => {
+      const api = require('../lib/api');
+      const events = require('../lib/common/Events');
+      for (const [className, classType] of Object.entries(api))
+        traceAPICoverage(coverageMap, events, className, classType);
+    },
+    afterAll: () => {
+      writeCoverage(coverageMap);
+    },
+  };
 };
 
 module.exports = {
diff --git a/test/mocha-utils.js b/test/mocha-utils.js
index 469545e2..d72b1803 100644
--- a/test/mocha-utils.js
+++ b/test/mocha-utils.js
@@ -140,7 +140,14 @@ global.describeChromeOnly = (...args) => {
   if (isChrome) return describe(...args);
 };
 
-if (process.env.COVERAGE) trackCoverage();
+let coverageHooks = {
+  beforeAll: () => {},
+  afterAll: () => {},
+};
+
+if (process.env.COVERAGE) {
+  coverageHooks = trackCoverage();
+}
 
 console.log(
   `Running unit tests with:
@@ -176,31 +183,39 @@ exports.setupTestPageAndContextHooks = () => {
   });
 };
 
-before(async () => {
-  const { server, httpsServer } = await setupServer();
+exports.mochaHooks = {
+  beforeAll: [
+    async () => {
+      const { server, httpsServer } = await setupServer();
 
-  state.puppeteer = puppeteer;
-  state.defaultBrowserOptions = defaultBrowserOptions;
-  state.server = server;
-  state.httpsServer = httpsServer;
-  state.isFirefox = isFirefox;
-  state.isChrome = isChrome;
-  state.isHeadless = isHeadless;
-  state.puppeteerPath = path.resolve(path.join(__dirname, '..'));
-});
+      state.puppeteer = puppeteer;
+      state.defaultBrowserOptions = defaultBrowserOptions;
+      state.server = server;
+      state.httpsServer = httpsServer;
+      state.isFirefox = isFirefox;
+      state.isChrome = isChrome;
+      state.isHeadless = isHeadless;
+      state.puppeteerPath = path.resolve(path.join(__dirname, '..'));
+    },
+    coverageHooks.beforeAll,
+  ],
 
-beforeEach(async () => {
-  state.server.reset();
-  state.httpsServer.reset();
-});
+  beforeEach: async () => {
+    state.server.reset();
+    state.httpsServer.reset();
+  },
 
-after(async () => {
-  await state.server.stop();
-  state.server = null;
-  await state.httpsServer.stop();
-  state.httpsServer = null;
-});
+  afterAll: [
+    async () => {
+      await state.server.stop();
+      state.server = null;
+      await state.httpsServer.stop();
+      state.httpsServer = null;
+    },
+    coverageHooks.afterAll,
+  ],
 
-afterEach(() => {
-  sinon.restore();
-});
+  afterEach: () => {
+    sinon.restore();
+  },
+};