Add missing types to tests.util. (#14597)

Removes files under tests.util from the ignored by list, then
fully types all tests/util/*.py files.

tests/util/test_async_helpers.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import traceback
+from typing import Generator, List, NoReturn, Optional
 
 from parameterized import parameterized_class
 
@@ -41,8 +42,8 @@ from tests.unittest import TestCase
 
 
 class ObservableDeferredTest(TestCase):
-    def test_succeed(self):
-        origin_d = Deferred()
+    def test_succeed(self) -> None:
+        origin_d: "Deferred[int]" = Deferred()
         observable = ObservableDeferred(origin_d)
 
         observer1 = observable.observe()
@@ -52,16 +53,18 @@ class ObservableDeferredTest(TestCase):
         self.assertFalse(observer2.called)
 
         # check the first observer is called first
-        def check_called_first(res):
+        def check_called_first(res: int) -> int:
             self.assertFalse(observer2.called)
             return res
 
         observer1.addBoth(check_called_first)
 
         # store the results
-        results = [None, None]
+        results: List[Optional[ObservableDeferred[int]]] = [None, None]
 
-        def check_val(res, idx):
+        def check_val(
+            res: ObservableDeferred[int], idx: int
+        ) -> ObservableDeferred[int]:
             results[idx] = res
             return res
 
@@ -72,8 +75,8 @@ class ObservableDeferredTest(TestCase):
         self.assertEqual(results[0], 123, "observer 1 callback result")
         self.assertEqual(results[1], 123, "observer 2 callback result")
 
-    def test_failure(self):
-        origin_d = Deferred()
+    def test_failure(self) -> None:
+        origin_d: Deferred = Deferred()
         observable = ObservableDeferred(origin_d, consumeErrors=True)
 
         observer1 = observable.observe()
@@ -83,16 +86,16 @@ class ObservableDeferredTest(TestCase):
         self.assertFalse(observer2.called)
 
         # check the first observer is called first
-        def check_called_first(res):
+        def check_called_first(res: int) -> int:
             self.assertFalse(observer2.called)
             return res
 
         observer1.addBoth(check_called_first)
 
         # store the results
-        results = [None, None]
+        results: List[Optional[ObservableDeferred[str]]] = [None, None]
 
-        def check_val(res, idx):
+        def check_val(res: ObservableDeferred[str], idx: int) -> None:
             results[idx] = res
             return None
 
@@ -103,10 +106,12 @@ class ObservableDeferredTest(TestCase):
             raise Exception("gah!")
         except Exception as e:
             origin_d.errback(e)
+        assert results[0] is not None
         self.assertEqual(str(results[0].value), "gah!", "observer 1 errback result")
+        assert results[1] is not None
         self.assertEqual(str(results[1].value), "gah!", "observer 2 errback result")
 
-    def test_cancellation(self):
+    def test_cancellation(self) -> None:
         """Test that cancelling an observer does not affect other observers."""
         origin_d: "Deferred[int]" = Deferred()
         observable = ObservableDeferred(origin_d, consumeErrors=True)
@@ -136,37 +141,38 @@ class ObservableDeferredTest(TestCase):
 
 
 class TimeoutDeferredTest(TestCase):
-    def setUp(self):
+    def setUp(self) -> None:
         self.clock = Clock()
 
-    def test_times_out(self):
+    def test_times_out(self) -> None:
         """Basic test case that checks that the original deferred is cancelled and that
         the timing-out deferred is errbacked
         """
-        cancelled = [False]
+        cancelled = False
 
-        def canceller(_d):
-            cancelled[0] = True
+        def canceller(_d: Deferred) -> None:
+            nonlocal cancelled
+            cancelled = True
 
-        non_completing_d = Deferred(canceller)
+        non_completing_d: Deferred = Deferred(canceller)
         timing_out_d = timeout_deferred(non_completing_d, 1.0, self.clock)
 
         self.assertNoResult(timing_out_d)
-        self.assertFalse(cancelled[0], "deferred was cancelled prematurely")
+        self.assertFalse(cancelled, "deferred was cancelled prematurely")
 
         self.clock.pump((1.0,))
 
-        self.assertTrue(cancelled[0], "deferred was not cancelled by timeout")
+        self.assertTrue(cancelled, "deferred was not cancelled by timeout")
         self.failureResultOf(timing_out_d, defer.TimeoutError)
 
-    def test_times_out_when_canceller_throws(self):
+    def test_times_out_when_canceller_throws(self) -> None:
         """Test that we have successfully worked around
         https://twistedmatrix.com/trac/ticket/9534"""
 
-        def canceller(_d):
+        def canceller(_d: Deferred) -> None:
             raise Exception("can't cancel this deferred")
 
-        non_completing_d = Deferred(canceller)
+        non_completing_d: Deferred = Deferred(canceller)
         timing_out_d = timeout_deferred(non_completing_d, 1.0, self.clock)
 
         self.assertNoResult(timing_out_d)
@@ -175,22 +181,24 @@ class TimeoutDeferredTest(TestCase):
 
         self.failureResultOf(timing_out_d, defer.TimeoutError)
 
-    def test_logcontext_is_preserved_on_cancellation(self):
-        blocking_was_cancelled = [False]
+    def test_logcontext_is_preserved_on_cancellation(self) -> None:
+        blocking_was_cancelled = False
 
         @defer.inlineCallbacks
-        def blocking():
-            non_completing_d = Deferred()
+        def blocking() -> Generator["Deferred[object]", object, None]:
+            nonlocal blocking_was_cancelled
+
+            non_completing_d: Deferred = Deferred()
             with PreserveLoggingContext():
                 try:
                     yield non_completing_d
                 except CancelledError:
-                    blocking_was_cancelled[0] = True
+                    blocking_was_cancelled = True
                     raise
 
         with LoggingContext("one") as context_one:
             # the errbacks should be run in the test logcontext
-            def errback(res, deferred_name):
+            def errback(res: Failure, deferred_name: str) -> Failure:
                 self.assertIs(
                     current_context(),
                     context_one,
@@ -209,7 +217,7 @@ class TimeoutDeferredTest(TestCase):
             self.clock.pump((1.0,))
 
             self.assertTrue(
-                blocking_was_cancelled[0], "non-completing deferred was not cancelled"
+                blocking_was_cancelled, "non-completing deferred was not cancelled"
             )
             self.failureResultOf(timing_out_d, defer.TimeoutError)
             self.assertIs(current_context(), context_one)
@@ -220,13 +228,13 @@ class _TestException(Exception):
 
 
 class ConcurrentlyExecuteTest(TestCase):
-    def test_limits_runners(self):
+    def test_limits_runners(self) -> None:
         """If we have more tasks than runners, we should get the limit of runners"""
         started = 0
         waiters = []
         processed = []
 
-        async def callback(v):
+        async def callback(v: int) -> None:
             # when we first enter, bump the start count
             nonlocal started
             started += 1
@@ -235,7 +243,7 @@ class ConcurrentlyExecuteTest(TestCase):
             processed.append(v)
 
             # wait for the goahead before returning
-            d2 = Deferred()
+            d2: "Deferred[int]" = Deferred()
             waiters.append(d2)
             await d2
 
@@ -265,16 +273,16 @@ class ConcurrentlyExecuteTest(TestCase):
         self.assertCountEqual(processed, [1, 2, 3, 4, 5])
         self.successResultOf(d2)
 
-    def test_preserves_stacktraces(self):
+    def test_preserves_stacktraces(self) -> None:
         """Test that the stacktrace from an exception thrown in the callback is preserved"""
-        d1 = Deferred()
+        d1: "Deferred[int]" = Deferred()
 
-        async def callback(v):
+        async def callback(v: int) -> None:
             # alas, this doesn't work at all without an await here
             await d1
             raise _TestException("bah")
 
-        async def caller():
+        async def caller() -> None:
             try:
                 await concurrently_execute(callback, [1], 2)
             except _TestException as e:
@@ -290,17 +298,17 @@ class ConcurrentlyExecuteTest(TestCase):
         d1.callback(0)
         self.successResultOf(d2)
 
-    def test_preserves_stacktraces_on_preformed_failure(self):
+    def test_preserves_stacktraces_on_preformed_failure(self) -> None:
         """Test that the stacktrace on a Failure returned by the callback is preserved"""
-        d1 = Deferred()
+        d1: "Deferred[int]" = Deferred()
         f = Failure(_TestException("bah"))
 
-        async def callback(v):
+        async def callback(v: int) -> None:
             # alas, this doesn't work at all without an await here
             await d1
             await defer.fail(f)
 
-        async def caller():
+        async def caller() -> None:
             try:
                 await concurrently_execute(callback, [1], 2)
             except _TestException as e:
@@ -336,7 +344,7 @@ class CancellationWrapperTests(TestCase):
         else:
             raise ValueError(f"Unsupported wrapper type: {self.wrapper}")
 
-    def test_succeed(self):
+    def test_succeed(self) -> None:
         """Test that the new `Deferred` receives the result."""
         deferred: "Deferred[str]" = Deferred()
         wrapper_deferred = self.wrap_deferred(deferred)
@@ -346,7 +354,7 @@ class CancellationWrapperTests(TestCase):
         self.assertTrue(wrapper_deferred.called)
         self.assertEqual("success", self.successResultOf(wrapper_deferred))
 
-    def test_failure(self):
+    def test_failure(self) -> None:
         """Test that the new `Deferred` receives the `Failure`."""
         deferred: "Deferred[str]" = Deferred()
         wrapper_deferred = self.wrap_deferred(deferred)
@@ -361,7 +369,7 @@ class CancellationWrapperTests(TestCase):
 class StopCancellationTests(TestCase):
     """Tests for the `stop_cancellation` function."""
 
-    def test_cancellation(self):
+    def test_cancellation(self) -> None:
         """Test that cancellation of the new `Deferred` leaves the original running."""
         deferred: "Deferred[str]" = Deferred()
         wrapper_deferred = stop_cancellation(deferred)
@@ -384,7 +392,7 @@ class StopCancellationTests(TestCase):
 class DelayCancellationTests(TestCase):
     """Tests for the `delay_cancellation` function."""
 
-    def test_deferred_cancellation(self):
+    def test_deferred_cancellation(self) -> None:
         """Test that cancellation of the new `Deferred` waits for the original."""
         deferred: "Deferred[str]" = Deferred()
         wrapper_deferred = delay_cancellation(deferred)
@@ -405,12 +413,12 @@ class DelayCancellationTests(TestCase):
         # Now that the original `Deferred` has failed, we should get a `CancelledError`.
         self.failureResultOf(wrapper_deferred, CancelledError)
 
-    def test_coroutine_cancellation(self):
+    def test_coroutine_cancellation(self) -> None:
         """Test that cancellation of the new `Deferred` waits for the original."""
         blocking_deferred: "Deferred[None]" = Deferred()
         completion_deferred: "Deferred[None]" = Deferred()
 
-        async def task():
+        async def task() -> NoReturn:
             await blocking_deferred
             completion_deferred.callback(None)
             # Raise an exception. Twisted should consume it, otherwise unwanted
@@ -434,7 +442,7 @@ class DelayCancellationTests(TestCase):
         # Now that the original coroutine has failed, we should get a `CancelledError`.
         self.failureResultOf(wrapper_deferred, CancelledError)
 
-    def test_suppresses_second_cancellation(self):
+    def test_suppresses_second_cancellation(self) -> None:
         """Test that a second cancellation is suppressed.
 
         Identical to `test_cancellation` except the new `Deferred` is cancelled twice.
@@ -459,7 +467,7 @@ class DelayCancellationTests(TestCase):
         # Now that the original `Deferred` has failed, we should get a `CancelledError`.
         self.failureResultOf(wrapper_deferred, CancelledError)
 
-    def test_propagates_cancelled_error(self):
+    def test_propagates_cancelled_error(self) -> None:
         """Test that a `CancelledError` from the original `Deferred` gets propagated."""
         deferred: "Deferred[str]" = Deferred()
         wrapper_deferred = delay_cancellation(deferred)
@@ -472,14 +480,14 @@ class DelayCancellationTests(TestCase):
         self.assertTrue(wrapper_deferred.called)
         self.assertIs(cancelled_error, self.failureResultOf(wrapper_deferred).value)
 
-    def test_preserves_logcontext(self):
+    def test_preserves_logcontext(self) -> None:
         """Test that logging contexts are preserved."""
         blocking_d: "Deferred[None]" = Deferred()
 
-        async def inner():
+        async def inner() -> None:
             await make_deferred_yieldable(blocking_d)
 
-        async def outer():
+        async def outer() -> None:
             with LoggingContext("c") as c:
                 try:
                     await delay_cancellation(inner())
@@ -503,7 +511,7 @@ class DelayCancellationTests(TestCase):
 class AwakenableSleeperTests(TestCase):
     "Tests AwakenableSleeper"
 
-    def test_sleep(self):
+    def test_sleep(self) -> None:
         reactor, _ = get_clock()
         sleeper = AwakenableSleeper(reactor)
 
@@ -518,7 +526,7 @@ class AwakenableSleeperTests(TestCase):
         reactor.advance(0.6)
         self.assertTrue(d.called)
 
-    def test_explicit_wake(self):
+    def test_explicit_wake(self) -> None:
         reactor, _ = get_clock()
         sleeper = AwakenableSleeper(reactor)
 
@@ -535,7 +543,7 @@ class AwakenableSleeperTests(TestCase):
 
         reactor.advance(0.6)
 
-    def test_multiple_sleepers_timeout(self):
+    def test_multiple_sleepers_timeout(self) -> None:
         reactor, _ = get_clock()
         sleeper = AwakenableSleeper(reactor)
 
@@ -555,7 +563,7 @@ class AwakenableSleeperTests(TestCase):
         reactor.advance(0.6)
         self.assertTrue(d2.called)
 
-    def test_multiple_sleepers_wake(self):
+    def test_multiple_sleepers_wake(self) -> None:
         reactor, _ = get_clock()
         sleeper = AwakenableSleeper(reactor)