Add wait argument to qtbot.assertNotEmitted

CHANGELOG.rst

@@ -3,6 +3,11 @@
 
 - Improve debugging output when no Qt wrapper was found.
 - Register the ``no_qt_log`` marker with pytest so ``--strict`` can be used.
+- ``qtbot.assertNotEmitted`` now has a new ``wait`` parameter which can be used
+  to make sure asynchronous signals aren't emitted by waiting after the code in
+  the ``with`` block finished.
+- ``qtbot.waitSignal`` with timeout ``0`` now expects the signal to arrive
+  directly in the code enclosed by it.
 
 3.0.2 (2018-08-31)
 ------------------

docs/signals.rst

@@ -98,6 +98,17 @@ parameters match, ``False`` otherwise.
             app.worker.start()
 
 
+timeout parameter
+----------------
+
+The ``timeout`` parameter specifies how long ``waitSignal`` should wait for a
+signal to arrive. If the timeout is ``None``, there won't be any timeout, i.e.
+it'll wait indefinitely.
+
+If the timeout is set to ``0``, it's expected that the signal arrives directly
+in the code inside the ``with qtbot.waitSignal(...):`` block.
+
+
 Getting arguments of the emitted signal
 ---------------------------------------
 
@@ -239,3 +250,14 @@ context manager:
         ...
         with qtbot.assertNotEmitted(app.worker.error):
             app.worker.start()
+
+By default, this only catches signals emitted directly inside the block.
+You can pass ``wait=...`` to wait for a given duration (in milliseconds) for
+asynchronous signals to (not) arrive:
+
+.. code-block:: python
+
+    def test_no_error(qtbot):
+        ...
+        with qtbot.assertNotEmitted(page.loadFinished, wait=100):
+            page.runJavaScript("document.getElementById('not-a-link').click()")

pytestqt/qtbot.py

@@ -435,19 +435,24 @@ def wait(self, ms):
         blocker.wait()
 
     @contextlib.contextmanager
-    def assertNotEmitted(self, signal):
+    def assertNotEmitted(self, signal, wait=0):
         """
         .. versionadded:: 1.11
 
         Make sure the given ``signal`` doesn't get emitted.
 
+        :param int wait:
+            How many milliseconds to wait to make sure the signal isn't emitted
+            asynchronously. By default, this method returns immediately and only
+            catches signals emitted inside the ``with``-block.
+
         This is intended to be used as a context manager.
 
         .. note:: This method is also available as ``assert_not_emitted``
                   (pep-8 alias)
         """
         spy = SignalEmittedSpy(signal)
-        with spy:
+        with spy, self.waitSignal(signal, timeout=wait, raising=False):
             yield
         spy.assert_not_emitted()
 

pytestqt/wait_signal.py

@@ -24,7 +24,7 @@ def __init__(self, timeout=1000, raising=True):
         self.raising = raising
         self._signals = None  # will be initialized by inheriting implementations
         self._timeout_message = ""
-        if timeout is None:
+        if timeout is None or timeout == 0:
             self._timer = None
         else:
             self._timer = qt_api.QtCore.QTimer(self._loop)
@@ -46,7 +46,10 @@ def wait(self):
         if self._timer is not None:
             self._timer.timeout.connect(self._quit_loop_by_timeout)
             self._timer.start()
-        self._loop.exec_()
+
+        if self.timeout != 0:
+            self._loop.exec_()
+
         if not self.signal_triggered and self.raising:
             raise TimeoutError(self._timeout_message)
 

tests/test_wait_signal.py

@@ -111,6 +111,21 @@ def test_signal_triggered(
     stop_watch.check(timeout, delay)
 
 
+@pytest.mark.parametrize("delayed", [True, False])
+def test_zero_timeout(qtbot, timer, delayed, signaller):
+    """
+    With a zero timeout, we don't run a main loop, so only immediate signals are
+    processed.
+    """
+    with qtbot.waitSignal(signaller.signal, raising=False, timeout=0) as blocker:
+        if delayed:
+            timer.single_shot(signaller.signal, 0)
+        else:
+            signaller.signal.emit()
+
+    assert blocker.signal_triggered != delayed
+
+
 @pytest.mark.parametrize(
     "configval, raises", [("false", False), ("true", True), (None, True)]
 )
@@ -1314,3 +1329,17 @@ def test_disconnected(self, qtbot, signaller):
         with qtbot.assertNotEmitted(signaller.signal):
             pass
         signaller.signal.emit()
+
+    def test_emitted_late(self, qtbot, signaller, timer):
+        with pytest.raises(SignalEmittedError):
+            with qtbot.assertNotEmitted(signaller.signal, wait=100):
+                timer.single_shot(signaller.signal, 10)
+
+    def test_continues_when_emitted(self, qtbot, signaller, stop_watch):
+        stop_watch.start()
+
+        with pytest.raises(SignalEmittedError):
+            with qtbot.assertNotEmitted(signaller.signal, wait=5000):
+                signaller.signal.emit()
+
+        stop_watch.check(4000)