Patch #1061904 / bug #878275: give a nicer error message when someone

accidentally derives from TestSuite instead of TestCase.

diff --git a/Lib/unittest.py b/Lib/unittest.py
index 3375067c8d07643090987db092f10b8e1a9a1931..70645fbce5db8a2c39d7b2200b612163601acadf 100644 (file)
--- a/Lib/unittest.py
+++ b/Lib/unittest.py
@@ -489,6 +489,8 @@ class TestLoader:
 
     def loadTestsFromTestCase(self, testCaseClass):
         """Return a suite of all tests cases contained in testCaseClass"""
+        if issubclass(testCaseClass, TestSuite):
+            raise TypeError("Test cases should not be derived from TestSuite. Maybe you meant to derive from TestCase?")
         testCaseNames = self.getTestCaseNames(testCaseClass)
         if not testCaseNames and hasattr(testCaseClass, 'runTest'):
             testCaseNames = ['runTest']