Better handling of KeyboardInterrupt

When we get a suspected KeyboardInterrupt (no result from Deferred),
explicitly stop the result and report the error as if it were a user
error.

NEWS

@@ -16,6 +16,12 @@ Improvements
 
 * Fixed example in ``failed`` docstring. (Jonathan Lange, Github #208)
 
+* Rather than explicitly raising a ``KeyboardInterrupt`` if we get no result
+  from a ``Deferred``, we tell the test result to stop running tests and
+  report the lack of result as a test error. This ought to make weird
+  concurrency interaction bugs easier to understand. (Jonathan Lange)
+
+
 2.0.0
 ~~~~~
 

testtools/tests/twistedsupport/test_runtest.py

@@ -469,8 +469,8 @@ class TestAsynchronousDeferredRunTest(NeedsTwistedTestCase):
         runner = self.make_runner(test, timeout * 5)
         result = self.make_result()
         reactor.callLater(timeout, os.kill, os.getpid(), SIGINT)
-        self.assertThat(lambda:runner.run(result),
-            Raises(MatchesException(KeyboardInterrupt)))
+        runner.run(result)
+        self.assertThat(result.shouldStop, Equals(True))
 
     @skipIf(os.name != "posix", "Sending SIGINT with os.kill is posix only")
     def test_fast_keyboard_interrupt_stops_test_run(self):
@@ -488,8 +488,8 @@ class TestAsynchronousDeferredRunTest(NeedsTwistedTestCase):
         runner = self.make_runner(test, timeout * 5)
         result = self.make_result()
         reactor.callWhenRunning(os.kill, os.getpid(), SIGINT)
-        self.assertThat(lambda:runner.run(result),
-            Raises(MatchesException(KeyboardInterrupt)))
+        runner.run(result)
+        self.assertThat(result.shouldStop, Equals(True))
 
     def test_timeout_causes_test_error(self):
         # If a test times out, it reports itself as having failed with a

testtools/twistedsupport/_runtest.py

@@ -395,7 +395,9 @@ class AsynchronousDeferredRunTest(_DeferredRunTest):
         except NoResultError:
             # We didn't get a result at all!  This could be for any number of
             # reasons, but most likely someone hit Ctrl-C during the test.
-            raise KeyboardInterrupt
+            self._got_user_exception(sys.exc_info())
+            self.result.stop()
+            return False, []
         except TimeoutError:
             # The function took too long to run.
             self._log_user_exception(TimeoutError(self.case, self._timeout))