TestSuite Objects
-----------------
`TestSuite' objects behave much like `TestCase' objects, except they do
not actually implement a test. Instead, they are used to aggregate
tests into groups that should be run together. Some additional methods
are available to add tests to `TestSuite' instances:
`addTest(test)'
Add a `TestCase' or `TestSuite' to the set of tests that make up
the suite.
`addTests(tests)'
Add all the tests from a sequence of `TestCase' and `TestSuite'
instances to this test suite.