I noticed there is an issue when running tests with the bridge (vendor/bin/simple-phpunit). When a test is annotate with @runInSeparateProcess the whole test suite is run.

For example if I run, the whole test suite is executed:

php /usr/local/bin/phpunit.phar src/.../Tests/Controller/MyTest.php --filter="testFoo"

/**
 * @runInSeparateProcess
 */
public function testFoo() {}

It's not the case when I remove @runInSeparateProcess or if I run phpunit without the bridge (but it's not supported with Symfony 3.3.2).