move UI unit tests away from PHP code and run directly in phantomjs w/ jasmine testing framework

[diosmosis]

Converting UI tests to JavaScript will confer many benefits including:

• Clearer test output (& no travis timing issues).
• Faster tests (we can setup just once for all tests & don't have to execute phantomjs multiple times).
• Clearer test code (via Jasmine's BDD style output).

Steps to complete:

• Move all of test environment setup to Fixture class. (done in uiunittests branch)
• Extend mocha & chai to handle screenshot compare use-case.
• Create JS script that will run a PHP program to setup the database and run each UI test suite.
• Modify existing UI tests.
• Modify travis config to run via phantomjs.

Reason for using Jasmine: phantomjs uses Jasmine internally for its tests so we know it'll work. mocha + chai can be used as an alternative.

CC-ing tsteur as per matt's request.

Update: Using mocha + chai is actually easier to get running and easier to extend.

[tsteur]

+1 for MochaJS see #4691

[diosmosis]

In 71dee21: Refs #4739, adding mocha + chai to tests/lib dir.

[diosmosis]

In 39c8961: Refs #4739, remove unneeded persist_fixture_data.

[diosmosis]

In f4e39c9: Refs #4739, #4189, remove persist_fixture_data config option code, placed OmniFixture into a namespace, removed PHP screenshot testcase classes and added fixture for use w/ JavaScript screenshot tests.

[diosmosis]

In f2faa23: Refs #4739, make sure recursive directory links are created even when --persist-fixture-data is used.

[tsteur]

@capedfuzz it would be cool if we could reuse some parts of this to write JavaScript unit tests for all the angular code

BTW: probably not really useful but just mention it... I built something similar a year ago to run tests using PhantomJS + Jasmine 2.0 but would now use MochaJS. Reckon there is not really anything new for you but just wanted to mention it. There is a testrunner https://github.com/tsteur/titanium-alloy-jasmine-testing/blob/master/tests.js and a loader https://github.com/tsteur/titanium-alloy-jasmine-testing/blob/master/specs/jasmine/utils/loader.js who finds all the test files in a specs directory: https://github.com/piwik/piwik-mobile-2/tree/master/specs

[diosmosis]

@tsteur If the tests for the angularjs code will run in a webpage, then you won't need any code I've written. The screenshot tests run directly in phantomjs, not in a webpage.

[diosmosis]

In bba1420: Refs #4739, allow JavaScript screenshot tests to override Piwik behavior by storing values in tmp/ file, add hook so plugins can setup their own test environment, reset user password on test fixture setup.

[diosmosis]

In bf92e42: Refs #4739, add console command to run UI tests.

[diosmosis]

In 35586df: Refs #4739, pass groups to new RunUITests console command.

[diosmosis]

In 8ba7f01: Refs #4739, move screenshot testing library code to core repository (from UI repository).

[diosmosis]

In 4ad2b98: Refs #4739, make sure UI screenshots are stored in plugin directories if tests are for plugins, cleaned up path output in console and add .gitignore to DBStats plugin.

[diosmosis]

In 8d72a9f: Refs #4739, fixing bug in processed screenshot dir path creation.

[diosmosis]

In ba6a60a: Refs #4739, add information about new UI tests to screenshot testing README.

[diosmosis]

In f073d10: Refs #4739, modify SyncUITestScreenshots command to work with new screenshot testing code and display location hint in diffviewer output if expected file is stored within plugin and not the UI tests repo.