Merge pull request #3424 from Polymer/fix-wct-mocha-6-compatibility

Bring in createStatsCollector from Mocha 6 as simple compatibility fix for Mocha 6 users

packages/wct-mocha/CHANGELOG.md

@@ -5,7 +5,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-<!-- ## Unreleased -->
+## Unreleased
+* Added support for Mocha 6.0.0, which introduced a breaking change related to initialization of stats on Mocha's test-runner, preventing reporting of test results.
 <!-- Add new, unreleased changes here. -->
 
 ## 1.0.0

packages/wct-mocha/src/reporters/console.ts

@@ -9,6 +9,7 @@
  * rights grant found at http://polymer.github.io/PATENTS.txt
  */
 import * as util from '../util.js';
+import {createStatsCollector} from './stats-collector.js';
 
 // We capture console events when running tests; so make sure we have a
 // reference to the original one.
@@ -81,6 +82,12 @@ export default class Console {
    * @param runner The runner that is being reported on.
    */
   constructor(runner: Mocha.IRunner) {
+    // Mocha 6 runner doesn't have stats at this point so we need to use
+    // the stats-collector from Mocha to add them before calling the base
+    // reporter.
+    if (!runner.stats) {
+      createStatsCollector(runner as unknown as Mocha.Runner);
+    }
     Mocha.reporters.Base.call(this, runner);
 
     runner.on(

packages/wct-mocha/src/reporters/stats-collector.ts

@@ -0,0 +1,94 @@
+'use strict';
+/**
+(The MIT License)
+
+Copyright (c) 2011-2018 JS Foundation and contributors, https://js.foundation
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+'Software'), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+/**
+ * The following was extracted from
+ * https://github.com/mochajs/mocha/blob/master/lib/stats-collector.js
+ */
+
+/**
+ * Test statistics collector.
+ *
+ * @typedef {Object} StatsCollector
+ * @property {number} suites - integer count of suites run.
+ * @property {number} tests - integer count of tests run.
+ * @property {number} passes - integer count of passing tests.
+ * @property {number} pending - integer count of pending tests.
+ * @property {number} failures - integer count of failed tests.
+ * @property {Date} start - time when testing began.
+ * @property {Date} end - time when testing concluded.
+ * @property {number} duration - number of msecs that testing took.
+ */
+
+/**
+ * Provides stats such as test duration,
+ * number of tests passed / failed etc.
+ *
+ * @public
+ * @memberof Mocha
+ * @param {Runner} runner
+ */
+export const createStatsCollector = (runner: Mocha.Runner) => {
+  var stats:
+      Mocha.Stats = {suites: 0, tests: 0, passes: 0, pending: 0, failures: 0};
+
+  if (!runner) {
+    throw new TypeError('Missing runner argument');
+  }
+
+  runner.stats = stats;
+
+  runner.once('start', function() {
+    stats.start = new Date();
+  });
+
+  runner.on('suite', function(suite) {
+    suite.root || stats.suites++;
+  });
+
+  runner.on('pass', function() {
+    stats.passes++;
+  });
+
+  runner.on('fail', function() {
+    stats.failures++;
+  });
+
+  runner.on('pending', function() {
+    stats.pending++;
+  });
+
+  runner.on('test end', function() {
+    stats.tests++;
+  });
+
+  runner.once('end', function() {
+    stats.end = new Date();
+    // To coerce to numbers and make TS compiler happy, we use unary `+` prefix
+    // for date arithmetic.
+    stats.duration = +stats.end - +stats.start;
+  });
+}

packages/wct-mocha/src/reporters/title.ts

@@ -9,6 +9,7 @@
  * rights grant found at http://polymer.github.io/PATENTS.txt
  */
 import * as util from '../util.js';
+import {createStatsCollector} from './stats-collector.js';
 
 const ARC_OFFSET = 0;  // start at the right.
 const ARC_WIDTH = 6;
@@ -21,6 +22,12 @@ const ARC_WIDTH = 6;
  */
 export default class Title {
   constructor(runner: Mocha.IRunner) {
+    // Mocha 6 runner doesn't have stats at this point so we need to use
+    // the stats-collector from Mocha to add them before calling the base
+    // reporter.
+    if (!runner.stats) {
+      createStatsCollector(runner as unknown as Mocha.Runner);
+    }
     Mocha.reporters.Base.call(this, runner);
 
     runner.on('test end', this.report.bind(this));