assorted test fixes & refactors (#4240)

- increase default timeout for wiggle room
- specify `watch-ignore` in case we run our own tests in watch mode
- reformat `.mocharc.yml`
- `integration/fixtures/uncaught/listeners.fixture.js`: reduce number of listeners created to avoid max listener warning
- `integration/fixtures/diffs.spec.js`: do not pass `-C`; the helper already does this
- `integration/options/watch.spec.js`: do not use context object; be more specific about spawn options. tweak timings
- `node-unit/mocha.spec.js`: make more unit-test-like insofar as that's possible when testing w/ `require()`
- `node-unit/cli/config.spec.js`: rewiremock fixes; assertion tweaks; add test for `.cjs` extension
- `node-unit/cli/options.spec.js`: rewiremock fixes; increase timeout
- `unit/hook-timeout.spec.js`: do not override default (configured) timeout
- `unit/runner.spec.js`: leverage [unexpected-eventemitter](https://npm.im/unexpected-eventemitter)
- `unit/throw.spec.js`: proper teardown: remove uncaught exception listeners
- `unit/timeout.spec.js`: increase timeout to _greater than_ default (configured) value
- `example/config/.mocharc.yml`: quote yaml strings

BONUS

- fixes a weird call to `Mocha.unloadFile()` from `Mocha#unloadFiles()`

Ref: #4198

.mocharc.yml

@@ -1,7 +1,14 @@
-require: test/setup
-ui: bdd
+require: 'test/setup'
+ui: 'bdd'
 global:
-  - okGlobalA,okGlobalB
-  - okGlobalC
-  - callback*
-timeout: 300
+  - 'okGlobalA,okGlobalB'
+  - 'okGlobalC'
+  - 'callback*'
+timeout: 1000
+watch-ignore:
+  - '.*'
+  - 'docs/_dist/**'
+  - 'docs/_site/**'
+  - 'node_modules'
+  - 'coverage'
+  - 'cache'

example/config/.mocharc.yml

@@ -8,40 +8,40 @@ delay: false
 diff: true
 exit: false # could be expressed as "no-exit: true"
 extension:
-  - js
+  - 'js'
 # fgrep and grep are mutually exclusive
 # fgrep: something
 file:
-  - /path/to/some/file
-  - /path/to/some/other/file
+  - '/path/to/some/file'
+  - '/path/to/some/other/file'
 forbid-only: false
 forbid-pending: false
 full-trace: false
 global:
-  - jQuery
-  - $
+  - 'jQuery'
+  - '$'
 # fgrep and grep are mutually exclusive
 # grep: something
 growl: false
 ignore:
-  - /path/to/some/ignored/file
+  - '/path/to/some/ignored/file'
 inline-diffs: false
 # needs to be used with grep or fgrep
 # invert: false
 opts: false
 recursive: false
-reporter: spec
+reporter: 'spec'
 reporter-option:
-  - foo=bar
-  - baz=quux
+  - 'foo=bar'
+  - 'baz=quux'
 require: '@babel/register'
 retries: 1
 slow: 75
 sort: false
-spec: test/**/*.spec.js # the positional arguments!
+spec: 'test/**/*.spec.js' # the positional arguments!
 timeout: false # same as "no-timeout: true" or "timeout: 0"
 trace-warnings: true # node flags ok
-ui: bdd
+ui: 'bdd'
 v8-stack-trace-limit: 100 # V8 flags are prepended with "v8-"
 watch: false
 watch-files:

lib/mocha.js

@@ -388,7 +388,9 @@ Mocha.unloadFile = function(file) {
  * @chainable
  */
 Mocha.prototype.unloadFiles = function() {
-  this.files.forEach(Mocha.unloadFile);
+  this.files.forEach(function(file) {
+    Mocha.unloadFile(file);
+  });
   return this;
 };
 

test/integration/diffs.spec.js

@@ -72,7 +72,7 @@ describe('diffs', function() {
   var diffs, expected;
 
   before(function(done) {
-    run('diffs/diffs.fixture.js', ['-C'], function(err, res) {
+    run('diffs/diffs.fixture.js', [], function(err, res) {
       if (err) {
         done(err);
         return;

test/integration/fixtures/uncaught/listeners.fixture.js

@@ -3,7 +3,8 @@
 const assert = require('assert');
 const mocha = require("../../../../lib/mocha");
 
-for (let i = 0; i < 15; i++) {
+// keep this low to avoid warning
+for (let i = 0; i < 5; i++) {
   const r = new mocha.Runner(new mocha.Suite("" + i, undefined));
   r.run();
 }