avoid global timers by way of ESLint; closes #3342 (#3374)

- Remove unused variables to avoid problems with #237 (and their associated inline ESLint directives)
- Use existing ESLint rules (`no-restricted-globals`, `no-restricted-modules` and `no-restricted-syntax`) to disallow global timer access.
- Removed "poison pill" tests in `test/unit/runnable.spec.js`.

For those rules, our config applies only to `bin/*` and `lib/**/*.js`.

- `no-restricted-globals`: Disallow bare references (including calls) to timers like `setTimeout`.
- `no-restricted-modules`: Disallow use of Node.js' `timers` module to get around the above restriction.
- `no-restricted-syntax`: 
  - Disallow calls of `global.setTimeout` and other timers
  - Disallow `new global.Date()`
  - Disallow any expressions involving `global.Date.*`, `global.setTimeout.*` and other timers

- add more files to markdown linting
- reorg tests, remove `fs` test from jsapi tests

.eslintrc.yml

@@ -28,12 +28,48 @@ overrides:
       ecmaVersion: 6
     env:
       browser: no
+
   - files:
       - test/**/*.{js,mjs}
     env:
       mocha: yes
     globals:
       expect: no
+  - files:
+    - bin/*
+    - lib/**/*.js
+    rules:
+      no-restricted-globals:
+        - error
+        - name: setTimeout
+          message: &GH-237 See https://github.com/mochajs/mocha/issues/237
+        - name: clearTimeout
+          message: *GH-237
+        - name: setInterval
+          message: *GH-237
+        - name: clearInterval
+          message: *GH-237
+        - name: setImmediate
+          message: *GH-237
+        - name: clearImmediate
+          message: *GH-237
+        - name: Date
+          message: *GH-237
+      no-restricted-modules:
+        - error
+        - timers
+      no-restricted-syntax:
+        - error
+        # disallow `global.setTimeout()`, `global.setInterval()`, etc.
+        - selector: 'CallExpression[callee.object.name=global][callee.property.name=/(set|clear)(Timeout|Immediate|Interval)/]'
+          message: *GH-237
+        # disallow `new global.Date()`
+        - selector: 'NewExpression[callee.object.name=global][callee.property.name=Date]'
+          message: *GH-237
+        # disallow property access of `global.<timer>.*`
+        - selector: '*[object.object.name=global][object.property.name=/(Date|(set|clear)(Timeout|Immediate|Interval))/]:expression'
+          message: *GH-237
+
   - files:
       - test/**/*.mjs
     parserOptions:

lib/reporters/base.js

@@ -18,19 +18,6 @@ var supportsColor = process.browser ? null : require('supports-color');
 
 exports = module.exports = Base;
 
-/**
- * Save timer references to avoid Sinon interfering.
- * See: https://github.com/mochajs/mocha/issues/237
- */
-
-/* eslint-disable no-unused-vars, no-native-reassign */
-var Date = global.Date;
-var setTimeout = global.setTimeout;
-var setInterval = global.setInterval;
-var clearTimeout = global.clearTimeout;
-var clearInterval = global.clearInterval;
-/* eslint-enable no-unused-vars, no-native-reassign */
-
 /**
  * Check if both stdio streams are associated with a tty.
  */

lib/reporters/html.js

@@ -18,13 +18,7 @@ var escape = utils.escape;
  * Save timer references to avoid Sinon interfering (see GH-237).
  */
 
-/* eslint-disable no-unused-vars, no-native-reassign */
 var Date = global.Date;
-var setTimeout = global.setTimeout;
-var setInterval = global.setInterval;
-var clearTimeout = global.clearTimeout;
-var clearInterval = global.clearInterval;
-/* eslint-enable no-unused-vars, no-native-reassign */
 
 /**
  * Expose `HTML`.

lib/reporters/xunit.js

@@ -17,14 +17,7 @@ var path = require('path');
 /**
  * Save timer references to avoid Sinon interfering (see GH-237).
  */
-
-/* eslint-disable no-unused-vars, no-native-reassign */
 var Date = global.Date;
-var setTimeout = global.setTimeout;
-var setInterval = global.setInterval;
-var clearTimeout = global.clearTimeout;
-var clearInterval = global.clearInterval;
-/* eslint-enable no-unused-vars, no-native-reassign */
 
 /**
  * Expose `XUnit`.

lib/runnable.js

@@ -8,15 +8,9 @@ var utils = require('./utils');
 /**
  * Save timer references to avoid Sinon interfering (see GH-237).
  */
-
-/* eslint-disable no-unused-vars, no-native-reassign */
 var Date = global.Date;
 var setTimeout = global.setTimeout;
-var setInterval = global.setInterval;
 var clearTimeout = global.clearTimeout;
-var clearInterval = global.clearInterval;
-/* eslint-enable no-unused-vars, no-native-reassign */
-
 var toString = Object.prototype.toString;
 
 module.exports = Runnable;

lib/stats-collector.js

@@ -21,6 +21,8 @@
  * @property {number} duration - number of msecs that testing took.
  */
 
+var Date = global.Date;
+
 /**
  * Provides stats such as test duration, number of tests passed / failed etc., by listening for events emitted by `runner`.
  *

package-scripts.js

@@ -36,7 +36,8 @@ module.exports = {
         description: 'Run ESLint linter'
       },
       markdown: {
-        script: 'markdownlint "*.md" "docs/**/*.md" ".github/*.md"',
+        script:
+          'markdownlint "*.md" "docs/**/*.md" ".github/*.md" "lib/**/*.md" "test/**/*.md" "example/**/*.md"',
         description: 'Run markdownlint linter'
       }
     },

test/integration/color.spec.js

@@ -0,0 +1,17 @@
+'use strict';
+
+var childProcess = require('child_process');
+var path = require('path');
+
+describe('mocha binary', function() {
+  it('should not output colors to pipe', function(done) {
+    var command = [path.join('bin', 'mocha'), '--grep', 'missing-test'];
+    childProcess.execFile(process.execPath, command, function(err, stdout) {
+      if (err) return done(err);
+
+      expect(stdout, 'not to contain', '[90m');
+
+      done();
+    });
+  });
+});

test/jsapi/index.js

@@ -18,7 +18,6 @@ mocha.addFile('test/unit/hook-sync.spec.js');
 mocha.addFile('test/unit/hook-sync-nested.spec.js');
 mocha.addFile('test/unit/hook-async.spec.js');
 mocha.addFile('test/unit/duration.spec.js');
-mocha.addFile('test/node-unit/fs.spec.js');
 mocha.addFile('test/unit/globals.spec.js');
 mocha.addFile('test/unit/timeout.spec.js');