We're using PHPUnit to add integration and unit tests at work and normally when I want to test a single I use --filter to pick just the one I want:

vagrant@precise64:/var/www$ vendor/bin/phpunit -c tests --filter UserTest::testLoginWithInvalidPassword
PHPUnit 3.7.31 by Sebastian Bergmann.

Configuration read from /var/www/tests/phpunit.xml

.......

Time: 6.82 seconds, Memory: 17.25Mb

OK (7 tests, 7 assertions)

Almost 7 seconds for 7 tests is a lot...

When I just just --filter PHPUnit is loading all the other unit test classes and then running just the ones that match the --filter. By specifiying the file I want to run the test from I can get better performance:

vagrant@precise64:/var/www$ vendor/bin/phpunit -c tests --filter UserTest::testLoginWithInvalidPassword tests/models/UserTest.php
PHPUnit 3.7.31 by Sebastian Bergmann.

Configuration read from /var/www/tests/phpunit.xml

.......

Time: 4.84 seconds, Memory: 12.50Mb

OK (7 tests, 7 assertions)

I'm sure for any PHPUnit masters this is old information but I've never seen it so I thought others might find it interesting.