Deluge testing is performed using Trial which is Twisted's testing framework and an extension of Python's unittest. Full documentation for Trial can be found on the Twisted website:
Here are some examples that show running all the test through to selecting an individual test.
For development branch (git master), tests are located in the source folder under 'deluge/tests'.
trial deluge trial deluge.tests.test_client trial deluge.tests.test_client.ClientTestCase trial deluge.tests.test_client.ClientTestCase.test_connect_localclient
For 1.3-stable, tests are located in the top level folder of source under tests.
cd tests trial *.py trial test_common trial test_common.CommonTestCase trial test_common.CommonTestCase.test_is_ip