You can use these to factor out code common to all tests in the test suite.
If you have a lot of repeated code in your tests, you can make them shorter by moving this code to setUp/tearDown.
You might use this for creating test data (e.g. setting up fakes/mocks), or stubbing out functions with fakes.
If you're doing integration testing, you can use check environmental pre-conditions in setUp, and skip the test if something isn't set up properly.
For example:
class TurretTest(unittest.TestCase):
def setUp(self):
self.turret_factory = TurretFactory()
self.turret = self.turret_factory.CreateTurret()
def test_turret_is_on_by_default(self):
self.assertEquals(True, self.turret.is_on())
def test_turret_turns_can_be_turned_off(self):
self.turret.turn_off()
self.assertEquals(False, self.turret.is_on())