Run peewee tests:

    $ python runtests.py (-e sqlite, -e postgres, -e mysql)

Run playhouse tests:

    $ python runtests.py -x (-e sqlite, -e postgres, -e mysql)

Run the entire suite, peewee and playhouse:

    $ python runtests.py -a (-e sqlite, -e postgres, -e mysql)

Run a specific TestCase:

    $ python tests.py TestCompoundSelectSQL

Run a specific test method:

    $ python tests.py TestCompoundSelectSQL.test_simple_same_model
