PHPUnit test suite include path

Your setUp() method gets called before every test, so testHandleSynchronousMessageForFailure() is also expecting sendNonBlockingAsynchronous() to be called:

$this->context->sendNonBlockingAsynchronous('platform_session_initiated', Argument::type("array"))
        ->shouldBeCalled();

Even if you call shouldNotBeCalled() on it in the failure test. So, move the shouldBeCalled() call to the testHandleSynchronousMessageForSuccess(), that way it will expect it to be called in the success test, and not to be called in the failure test.

You should also tell PHPUnit to expect an IdNotDefinedException in the failure test:

$this->expectException(GpxExceptionsIdNotDefinedException::class);

There are a number of ways to not run a particular test - putting it into a blacklist so it's never run may not be the way - as changing it means editing the blacklist, and you'll often endup bouncing it in and out of version control.

There are several other ways that may be more appropriate:

If a test is not yet ready to run:

$this->markTestIncomplete('This test has not been implemented yet.');

If there's an outside reason it should not be run, skip it:

if (!extension_loaded('mysqli')) {
    $this->markTestSkipped('The MySQLi extension is not available.');
}

You can also put that into the setUp() function, so it will skip all the tests in a test-class.

You can make a test dependant on a previous one succeeding:

public function testEmpty()
{
    $stack = array();
    $this->assertTrue(empty($stack));
    return $stack;   // also sends this variable to any following tests - if this worked
}
/**
 * only runs if testEmpty() passed
 *
 * @depends testEmpty
 */
public function testPush(array $stack)
{
}

The @group -name- annotation is one of the best ways to specifically stop, or run one group of tests

/**
 * @group database
 * @group remoteTasks
 */
public function testSomething()
{
}

testSomething() is now in two groups, and if either is added on the command line (or in the config.xml) --exclude-group parameter. it won't be run. Likewise, you could run only tests that belong to a particular group - say named after a feature, or bug report.