LocalBearTestHelper: Return results for checking

Sometimes, the check_validity() function can be used to get results and
then do additional checks on the results. It's useful to give out the
results in such cases.

tests/LocalBearTestHelper.py

@@ -89,6 +89,7 @@ def check_validity(self,
                 msg = ("The local bear '{}' yields no result although it "
                        "should.".format(local_bear.__class__.__name__))
                 self.assertNotEqual(len(bear_output), 0, msg=msg)
+            return bear_output
 
     def check_results(self,
                       local_bear,