When you are creating new tests with PHPUnit, if you execute all tests, it can take some time to execute. To execute them faster, you can filter the tests you want to execute.
Executing one test
To execute only one test, you can use the --filter parameter and the test method you want to test:
./vendor/bin/phpunit --filter test_my_test
Executing all tests in a file
To execute all tests in a file, you can use the same --filter parameter and the class you want to test:
./vendor/bin/phpunit --filter My_test_class
More information available in the official documentation.