Core tests: set up abstract class and remove code duplication

[jrfnl]

Note: this PR will be easiest to review by looking at the individual commits.

I've created this PR as a precursor to #2189 (move utility methods to static classes) as most of the new utility functions which are mentioned in that issue will be accompanied by unit tests when they are pulled.

Improving the setup of the utility function testing, as done in this PR, will make that so much simpler.

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Commit Summary

New Tests\Core\AbstractMethodUnitTest class

Refactor to remove duplicate code.

This new class abstracts out the setUp() and tearDown() methods which were included in nearly all the utility method test classes.

The methods have been changed to static setUpBeforeClass() and tearDownAfterClass() with a static property as the initial processed File doesn't change between tests, so there is no need to tokenize and process the unit test case file for each test individually.

This makes the utility method unit tests significantly faster as well as lower the memory usage.

Additionally, the standard against which the files are processed has been changed from Generic (75 sniffs) to PSR1 (7 sniffs), which, again, makes the unit test suite for the Core utility functions significantly faster.

The current implementation allows for only one test case file per utility method test file, but as the utility method tests are not sniff specific, adding additional tests files for a method if needed, should not be a problem.

By default test case files are expected to be PHP inc files. Child classes can overload the static $fileExtension property when the test case file is a JS or CSS file.

Implement use of the new AbstractMethodUnitTest class

... in the various utility method unit test classes.

Tests\Core\AbstractMethodUnitTest: add new getTargetToken() method

This adds a new getTargetToken() method which can retrieve the target token for testing with higher precision than the (duplicate) code which was so far used in the individual test methods.

The improvements this method offers are:

• Avoid test leaking/contamination.
  If/when the token to start the test from was retrieved by doing a findNext() from the delimiter comment, a typo could cause a token from the next test to be used for the testing instead of the target token.
  If the expected results would be the same for both tests, this would go completely unnoticed.
  This is now no longer possible.
  The only requirement is that the delimiter comments start with /* test....
• No more token counting when setting up the unit tests, just pass the target token type constant to this method and it will get you the correct token.
  This also allows for not having to jump through hoops when deciding where to place the delimiter comment for the test.
• If the token a test looks for is a T_STRING or text based token, the optional $tokenContent allows for selecting the correct token, even when there are several of the same type in the test case line.

Implement use of the new AbstractMethodUnitTest::getTargetToken() method

... in the various utility method unit test classes.

GetMethodParametersTest: remove even more duplicate code

GetMethodPropertiesTest: remove even more duplicate code

Implement use of the new AbstractMethodUnitTest::getTargetToken() method as well as abstract out the actual testing to a helper method as the logic was the same in all methods.

I've chosen not to implement this with a data provider as the separate test methods creating the $expected arrays make the tests more readable and easier to understand.

Tests\Core\AllTests: simplify creation of the test suite

As the refactor will add a lot of new unit test files, let's automate the creation of the test suite some more by automatically adding all Test files within the Test\Core directory.

[jrfnl]

Rebased for imaginary merge conflict.

[jrfnl]

Could this PR be milestoned to 3.5.0 please ? It's a prerequisite for the utility method refactor.

[jrfnl]

I've added an additional commit to this PR which simplifies the creation of the Core/utility method test suite as new tests don't need to be added manually anymore, but will automatically be included.

[jrfnl]

As discussed in #2189, this commit is included within #2456.

[jrfnl]

I've rebased this PR, fixed the merge conflicts and added two additional commits and minor changes in the existing commits.

The significant differences with the original PR:

• Moved the FileList class to the tests directory as per feedback in [WIP] PHPCS 3.5.0: refactor utility methods and add additional utility methods #2456.
  Includes making the necessary changes to the ValidatePEARPackageXML functionality to allow for this.
• Actually use the FileList Iterator in the Core\AllTests class instead of using an interim array.
• Removed the unset()s for the token positions from the GetMethodParametersTest, GetMethodPropertiesTest and GetMemberPropertiesTest and switched the assertSame() to a strict assertArraySubset().
  Ref: https://phpunit.de/manual/4.8/en/appendixes.assertions.html#appendixes.assertions.assertArraySubset

[gsherwood]

Thanks a lot for updating this PR.

The core test speed improvement was so noticeable that I had to go and break things just to make sure they were still running :)