bpo-33746: Fix test_unittest.testRegisterResult() in verbose mode (GH-7799)

Only make sure that the result is in unittest.signals._results, don't
check the full content of unittest.signals._results.

support._run_suite() uses TextTestRunner in verbose mode, but
TextTestRunner.run() calls registerResult(result) which made the test
fail with "odd object in result set".

Call also removeResult() to restore unittest.signals._results to
avoid test side effect.

1 files changed, 6 insertions, 9 deletions

diff --git a/Lib/unittest/test/test_break.py b/Lib/unittest/test/test_break.py
index aa2c69eea0..eebd2b610c 100644
--- a/Lib/unittest/test/test_break.py
+++ b/Lib/unittest/test/test_break.py
@@ -39,16 +39,13 @@ class TestBreak(unittest.TestCase):
 
     def testRegisterResult(self):
         result = unittest.TestResult()
-        unittest.registerResult(result)
-
-        for ref in unittest.signals._results:
-            if ref is result:
-                break
-            elif ref is not result:
-                self.fail("odd object in result set")
-        else:
-            self.fail("result not found")
+        self.assertNotIn(result, unittest.signals._results)
 
+        unittest.registerResult(result)
+        try:
+            self.assertIn(result, unittest.signals._results)
+        finally:
+            unittest.removeResult(result)
 
     def testInterruptCaught(self):
         default_handler = signal.getsignal(signal.SIGINT)