[Twirrim]

It's also worth noting that not even PHP itself passes their own test suite. At the time of writing http://gcov.php.net/viewer.php?version=PHP_5_5 states:

Overview of PHP_5_5

Build Status: OK Last Build Time: 2 days

Compile Warnings: 611 Code Coverage: 0.3% Test Failures: 78 Expected Test Failures: 42 Valgrind Reports: 44

The "Expected Test Failures" is fascinating. http://gcov.php.net/viewer.php?version=PHP_5_5&func=expected...

[TazeTSchnitzel]

That's true, but PHP still passes the vast majority of its tests.