Unit Tests cannot be loaded from extension directories due to a particular path expected in PHPUnit_Runner_StandardTestSuiteLoader.php

At the code sprint we found that we couldn't run phpunit tests with the scripts/phpunit or civix test command when the tests were in an extensions folder. We were getting an error "Class %s could not be found in %s. We tracked this down to PHPUnit_Runner_StandardTestSuiteLoader.php enforcing all tests to be in a global base_dir/tests/phpunit. The fix scans the include directories as well in an attempt to load the tests - this does work and lets the extension tests run from the civix test command.

I will be sending a pull request with this issue #.