While looking for long running Integration tests (#12691) I saw, that the test
Piwik\Tests\Integration\ServeStaticFileTest:test_nonReadableFile takes around 65s on travis, as reading the file without permission seems to take a long time.
Adding a check for
is_readable speeds up the test to less than 10 seconds (guess even less, but I used 10 seconds for reporting slow tests).
Not sure if that might decrease the speed for existing files as there is another file operation to be done...
Feel free to merge if it increases the speed 👍