diff -r 7a62b5ee32ec Lib/unittest/case.py
--- a/Lib/unittest/case.py	Thu Jan 10 11:15:57 2013 -0500
+++ b/Lib/unittest/case.py	Fri Jan 11 10:42:35 2013 +0200
@@ -411,6 +411,8 @@
             outcome.errors.append(sys.exc_info())
 
     def run(self, result=None):
+        _checkTestOverriding(self.__class__, self._testMethodName)
+        return
         orig_result = result
         if result is None:
             result = self.defaultTestResult()
@@ -1213,3 +1215,17 @@
             return self._description
         doc = self._testFunc.__doc__
         return doc and doc.split("\n")[0].strip() or None
+
+def _checkTestOverriding(cls, methodName):
+    method = getattr(cls, methodName)
+    for c in cls.__mro__:
+        m = getattr(c, methodName, None)
+        if m is None:
+            continue
+        if m != method:
+#            warnings.warn('%s: %s method in %s hides the test in %s' %
+#                          (cls.__module__, methodName, cls.__qualname__, c.__qualname__),
+#                          RuntimeWarning, 2)
+            print('%s: %s method in %s hides the test in %s' %
+                  (cls.__module__, methodName, cls.__qualname__, c.__qualname__), file=sys.stderr)
+            return