test_faulthandler: improve the test on dump_tracebacks_later(cancel=True)

Lib/test/test_faulthandler.py

@@ -358,22 +358,16 @@ import faulthandler
 import time
 
 def func(repeat, cancel, timeout):
-    pause = timeout * 2.5
-    # on Windows XP, b-a gives 1.249931 after sleep(1.25)
-    min_pause = pause * 0.9
-    a = time.time()
-    time.sleep(pause)
+    if cancel:
         faulthandler.cancel_dump_tracebacks_later()
-    b = time.time()
-    # Check that sleep() was not interrupted
-    assert (b - a) >= min_pause, "{{}} < {{}}".format(b - a, min_pause)
 
-    if cancel:
-        pause = timeout * 1.5
+    pause = timeout * 2.5
+    # on Windows XP, b-a gives 1.249931 after sleep(1.25)
     min_pause = pause * 0.9
     a = time.time()
     time.sleep(pause)
     b = time.time()
+    faulthandler.cancel_dump_tracebacks_later()
     # Check that sleep() was not interrupted
     assert (b - a) >= min_pause, "{{}} < {{}}".format(b - a, min_pause)
 
@@ -400,13 +394,16 @@ if file is not None:
         trace, exitcode = self.get_output(code, filename)
         trace = '\n'.join(trace)
 
+        if not cancel:
             if repeat:
                 count = 2
             else:
                 count = 1
             header = 'Thread 0x[0-9a-f]+:\n'
-        regex = expected_traceback(9, 33, header, count=count)
+            regex = expected_traceback(12, 27, header, count=count)
             self.assertRegex(trace, regex)
+        else:
+            self.assertEqual(trace, '')
         self.assertEqual(exitcode, 0)
 
     @unittest.skipIf(not hasattr(faulthandler, 'dump_tracebacks_later'),
@@ -425,8 +422,8 @@ if file is not None:
     def test_dump_tracebacks_later_repeat(self):
         self.check_dump_tracebacks_later(repeat=True)
 
-    def test_dump_tracebacks_later_repeat_cancel(self):
-        self.check_dump_tracebacks_later(repeat=True, cancel=True)
+    def test_dump_tracebacks_later_cancel(self):
+        self.check_dump_tracebacks_later(cancel=True)
 
     def test_dump_tracebacks_later_file(self):
         self.check_dump_tracebacks_later(file=True)