tests: Make sure testprocess raises if start fails.

tests/integration/test_testprocess.py

@@ -81,6 +81,14 @@ def pyproc():
     proc.terminate()
 
 
+def test_wait_signal_raising(qtbot):
+    """testprocess._wait_signal should raise by default."""
+    proc = testprocess.Process()
+    with pytest.raises(qtbot.SignalTimeoutError):
+        with proc._wait_signal(proc.proc.started, timeout=0):
+            pass
+
+
 class TestWaitFor:
 
     def test_successful(self, pyproc):

tests/integration/testprocess.py

@@ -172,7 +172,7 @@ class Process(QObject):
         self.read_log()
         return self._data
 
-    def _wait_signal(self, signal, timeout=5000, raising=None):
+    def _wait_signal(self, signal, timeout=5000, raising=True):
         """Wait for a signal to be emitted.
 
         Should be used in a contextmanager.