b4f95deefc9d456c5a2d0f6338f6dcecc0829652 suggests that this can lead to issues with classes having the same name. However, this does not seem to be a problem with the current version of PHPUnit we are using. Despite https://phpunit.de/manual/4.1/en/code-coverage-analysis.html saying that addUncoveredFilesFromWhitelist="true" is optional, this seems to be on by default in PHPUnit 4.1.0. As a result, all files are considered for code coverage; which is what we want. processUncoveredFilesFromWhitelist is however false (by default) and as such even files that are considered for code coverage are not processed through PHP when not used in actual tests. Since it is already impossible to test multiple classes with the same name in the same test run (without process isolation), because that would already lead to "cannot redeclare class" errors, it is also impossible for "cannot redeclare class" errors to happen in test coverage. PHPBB3-13341