Hi All, I tried to run test cases for jvm backend by the following command, pypy pypy/test_all.py rpython/translator/jvm/test but what I got was 10 tests defined in rpython/translator/jvm/test/test_backendopt.py although there are two dozens of test files in that directory. After experiment, I found that it failed to collect test within a multi inherited class. Take test_constant.py as an example, it defines a class, class TestConstant(BaseTestConstant, JvmTest): pass and JvmTest is defined as, class JvmTest(BaseRtypingTest, OORtypeMixin): ...... When I executed the folloing, ypy pypy/test_all.py rpython/translator/jvm/test/test_constant.py --collectonly it reported 0 item was collected. If I remove BaseTestConstant from TestConstant's super classes, it still reports 0 item collected; but if I remove JvmTest from its super classes, it reports 18 items are collected. I'm wondering how the daily test solve this problem? Thanks, James Lan