Add Settings bluetooth page test

chrome/test/data/webui/mocha_adapter.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview A mocha adapter for BrowserTests. To use, include mocha.js and
  * mocha_adapter.js in a WebUIBrowserTest's extraLibraries array.
  */
 
+// NOTE: When defining TEST_F() functions that use Mocha, use 'var self = this'
+// for referencing the Test object within suite() and test() function objects
+// (instead of binding |this|), since |this| within those objects will reference
+// the Mocha Suite or Test instance.

[Dan Beam, 2015/12/28 20:01:39]

this is probably more a general understanding of |this| in JS, though I suppose
it doesn't hurt.  are the test cases actually being .call()'d or .apply()'d with
different objects?

[michaelpg, 2015/12/28 20:39:35]

Yes, the test cases are call'd or apply'd on a particular object, the Context
object.

This can be used to change timeouts, e.g.:

test('foo', function() {
  this.timeout(0);
});

It can also be used to share data between tests and other hooks, which looks
like a terrible idea:
https://github.com/mochajs/mocha/wiki/Shared-Behaviours


I'm kind of on the fence as to whether it's okay to bind these functions to
`this`:

test('foo', function() {
  this.getSettingsPage();
}.bind(this));

I don't think that will break Mocha, but it can lead to an annoyingly high
number of .bind calls with nested suites.

[stevenjb, 2015/12/28 20:49:16]

There has been some confusion and discussion about the right model (whether to
use 'self' or .bind(this)), which is why I added the comment. I'm not certain
how mocha invokes the suites/tests. We may want to discuss this further.

+
 /**
  * Initializes a mocha reporter for the BrowserTest framework, which registers
  * event listeners on the given Runner.
  * @constructor
  * @param {Runner} runner Runs the tests and provides hooks for test results
  *     (see Runner.prototype in mocha.js).
  */
 function BrowserTestReporter(runner) {
   var passes = 0;
   var failures = 0;
@@ skipping 37 matching lines @@
 mocha.setup({
   // Use TDD interface instead of BDD.
   ui: 'tdd',
   // Use custom reporter to interface with BrowserTests.
   reporter: BrowserTestReporter,
   // Mocha timeouts are set to 2 seconds initially. This isn't nearly enough for
   // slower bots (e.g., Dr. Memory). Disable timeouts globally, because the C++
   // will handle it (and has scaled timeouts for slower bots).
   enableTimeouts: false,
 });