Skip the test if the specified type is not being run.

Integration tests require a mongod running on localhost:33333.

Kerberos tests are a special type of integration test that test tools with Kerberos authentication against the drivers Kerberos testing cluster because setting up a KDC every time is too brittle and expensive.

"ssl" and "auth" are used to configure integration tests to run against different mongod configurations.

Unit tests don't require a real mongod.