I've run into a problem trying to run the same tests against a bunch of different classes.

A shared test case contains the test methods which I want to run against all the classes. Each class has its own test case which extends the shared test case (which in turn extends the UnitTestCase, of course ). Any additional tests for a particular class can be added here.

The shared test case uses factory methods implemented by each of the derived test cases so that different objects can be supplied to the tests - including objects of each class to be tested.

This works fine when I run the tests one at a time but not when I add them all to a group test. In the group test, the factory methods have not been implemented, objects aren't being created, and the group test will not run.

Is this something to do with the way group tests are combined?