Merge pull request #29 by @graingert

.travis.yml

@@ -18,5 +18,5 @@ install:
   - pipenv run pip install PyQt5 PySide2
 
 script:
-  - QT_API=PyQt5 pipenv run py.test -v 
-  - QT_API=PySide2 pipenv run py.test -v 
+  - QT_API=PyQt5 pipenv run py.test --forked -v
+  - QT_API=PySide2 pipenv run py.test --forked -v

Pipfile

@@ -7,6 +7,7 @@ verify_ssl = true
 pytest = "*"
 pathlib2 = "*"
 atomicwrites = "*"
+pytest-forked = "*"
 
 [packages]
 

examples/aiohttp_fetch.py

@@ -2,11 +2,11 @@
 import asyncio
 
 import aiohttp
-from qasync import QEventLoop, asyncSlot, asyncClose
+from qasync import run, asyncSlot, asyncClose
 
 # from PyQt5.QtWidgets import (
 from PySide2.QtWidgets import (
-    QApplication, QWidget, QLabel, QLineEdit, QTextEdit, QPushButton,
+    QWidget, QLabel, QLineEdit, QTextEdit, QPushButton,
     QVBoxLayout)
 
 
@@ -61,13 +61,12 @@ async def on_btnFetch_clicked(self):
             self.btnFetch.setEnabled(True)
 
 
-if __name__ == '__main__':
-    app = QApplication(sys.argv)
-    loop = QEventLoop(app)
-    asyncio.set_event_loop(loop)
-
+async def main():
+    loop = asyncio.get_running_loop()
     mainWindow = MainWindow()
     mainWindow.show()
+    await loop.create_future()
+
 
-    with loop:
-        sys.exit(loop.run_forever())
+if __name__ == "__main__":
+    qasync.run(main())

examples/executor_example.py

@@ -8,19 +8,15 @@
 from qasync import QEventLoop, QThreadExecutor
 
 
-app = QApplication(sys.argv)
-loop = QEventLoop(app)
-asyncio.set_event_loop(loop)
-
-progress = QProgressBar()
-progress.setRange(0, 99)
-progress.show()
-
-
 async def master():
+    progress = QProgressBar()
+    progress.setRange(0, 99)
+    progress.show()
+
     await first_50()
+    loop = asyncio.get_running_loop()
     with QThreadExecutor(1) as exec:
-        await loop.run_in_executor(exec, last_50)
+        await loop.run_in_executor(exec, last_50, loop)
 
 
 async def first_50():
@@ -29,11 +25,10 @@ async def first_50():
         await asyncio.sleep(.1)
 
 
-def last_50():
+def last_50(loop):
     for i in range(50, 100):
         loop.call_soon_threadsafe(progress.setValue, i)
         time.sleep(.1)
 
 
-with loop:
-    loop.run_until_complete(master())
+qasync.run(master())

qasync/__init__.py

@@ -20,6 +20,7 @@
 __all__ = ["QEventLoop", "QThreadExecutor", "asyncSlot", "asyncClose"]
 
 import asyncio
+import contextlib
 import functools
 import importlib
 import itertools
@@ -532,9 +533,8 @@ def __notifier_cb_wrapper(self, notifiers, notifier, fd, callback, args):
     def __on_notifier_ready(self, notifiers, notifier, fd, callback, args):
         if fd not in notifiers:
             self._logger.warning(
-                "Socket notifier for fd {} is ready, even though it should be disabled, not calling {} and disabling".format(
-                    fd, callback
-                ),
+                f"Socket notifier for fd {fd} is ready, even though it should "
+                f"be disabled, not calling {callback} and disabling"
             )
             notifier.setEnabled(False)
             return
@@ -727,3 +727,30 @@ def wrapper(*args, **kwargs):
         return wrapper
 
     return outer_decorator
+
+
+class QEventLoopPolicyMixin:
+    def new_event_loop(self):
+        return QEventLoop(QApplication(sys.argv))
+
+
+class DefaultQEventLoopPolicy(
+    QEventLoopPolicyMixin,
+    asyncio.DefaultEventLoopPolicy,
+):
+    pass
+
+
+@contextlib.contextmanager
+def _set_event_loop_policy(policy):
+    old_policy = asyncio.get_event_loop_policy()
+    asyncio.set_event_loop_policy(policy)
+    try:
+        yield
+    finally:
+        asyncio.set_event_loop_policy(old_policy)
+
+
+def run(*args, **kwargs):
+    with _set_event_loop_policy(DefaultQEventLoopPolicy()):
+        return asyncio.run(*args, **kwargs)