Add asyncio.run_forever(); add tests.

asyncio/__init__.py

@@ -24,7 +24,7 @@
 from .futures import *
 from .locks import *
 from .protocols import *
-from .run import *
+from .runners import *
 from .queues import *
 from .streams import *
 from .subprocess import *
@@ -37,12 +37,12 @@
            futures.__all__ +
            locks.__all__ +
            protocols.__all__ +
+           runners.__all__ +
            queues.__all__ +
            streams.__all__ +
            subprocess.__all__ +
            tasks.__all__ +
-           transports.__all__ +
-           ['run'])  # Will fix this later.
+           transports.__all__)
 
 if sys.platform == 'win32':  # pragma: no cover
     from .windows_events import *

asyncio/runners.py

@@ -0,0 +1,146 @@
+"""asyncio.run() and asyncio.run_forever() functions."""
+
+__all__ = ['run', 'run_forever']
+
+import inspect
+import threading
+
+from . import coroutines
+from . import events
+
+
+def _cleanup(loop):
+    try:
+        # `shutdown_asyncgens` was added in Python 3.6; not all
+        # event loops might support it.
+        shutdown_asyncgens = loop.shutdown_asyncgens
+    except AttributeError:
+        pass
+    else:
+        loop.run_until_complete(shutdown_asyncgens())
+    finally:
+        events.set_event_loop(None)
+        loop.close()
+
+
+def run(main, *, debug=False):
+    """Run a coroutine.
+
+    This function runs the passed coroutine, taking care of
+    managing the asyncio event loop and finalizing asynchronous
+    generators.
+
+    This function must be called from the main thread, and it
+    cannot be called when another asyncio event loop is running.
+
+    If debug is True, the event loop will be run in debug mode.
+
+    This function should be used as a main entry point for
+    asyncio programs, and should not be used to call asynchronous
+    APIs.
+
+    Example::
+
+        async def main():
+            await asyncio.sleep(1)
+            print('hello')
+
+        asyncio.run(main())
+    """
+    if events._get_running_loop() is not None:
+        raise RuntimeError(
+            "asyncio.run() cannot be called from a running event loop")
+    if not isinstance(threading.current_thread(), threading._MainThread):
+        raise RuntimeError(
+            "asyncio.run() must be called from the main thread")
+    if not coroutines.iscoroutine(main):
+        raise ValueError("a coroutine was expected, got {!r}".format(main))
+
+    loop = events.new_event_loop()
+    try:
+        events.set_event_loop(loop)
+
+        if debug:
+            loop.set_debug(True)
+
+        return loop.run_until_complete(main)
+    finally:
+        _cleanup(loop)
+
+
+def run_forever(main, *, debug=False):
+    """Run asyncio loop.
+
+    main must be an asynchronous generator with one yield, separating
+    program initialization from cleanup logic.
+
+    If debug is True, the event loop will be run in debug mode.
+
+    This function should be used as a main entry point for
+    asyncio programs, and should not be used to call asynchronous
+    APIs.
+
+    Example:
+
+        async def main():
+            server = await asyncio.start_server(...)
+            try:
+                yield  # <- Let event loop run forever.
+            except KeyboardInterrupt:
+                print('^C received; exiting.')
+            finally:
+                server.close()
+                await server.wait_closed()
+
+        asyncio.run_forever(main())
+    """
+    if not hasattr(inspect, 'isasyncgen'):
+        raise NotImplementedError
+
+    if events._get_running_loop() is not None:
+        raise RuntimeError(
+            "asyncio.run_forever() cannot be called from a running event loop")
+    if not isinstance(threading.current_thread(), threading._MainThread):
+        raise RuntimeError(
+            "asyncio.run() must be called from the main thread")
+    if not inspect.isasyncgen(main):
+        raise ValueError(
+            "an asynchronous generator was expected, got {!r}".format(main))
+
+    loop = events.new_event_loop()
+    try:
+        events.set_event_loop(loop)
+        if debug:
+            loop.set_debug(True)
+
+        ret = None
+        try:
+            ret = loop.run_until_complete(main.asend(None))
+        except StopAsyncIteration as ex:
+            return
+        if ret is not None:
+            raise RuntimeError("only empty yield is supported")
+
+        yielded_twice = False
+        try:
+            loop.run_forever()
+        except BaseException as ex:
+            try:
+                loop.run_until_complete(main.athrow(ex))
+            except StopAsyncIteration as ex:
+                pass
+            else:
+                yielded_twice = True
+        else:
+            try:
+                loop.run_until_complete(main.asend(None))
+            except StopAsyncIteration as ex:
+                pass
+            else:
+                yielded_twice = True
+
+        if yielded_twice:
+            raise RuntimeError("only one yield is supported")
+
+    finally:
+        _cleanup(loop)

runtests.py

@@ -112,6 +112,10 @@ def list_dir(prefix, dir):
             print("Skipping '{0}': need at least Python 3.5".format(modname),
                   file=sys.stderr)
             continue
+        if modname == 'test_runner' and (sys.version_info < (3, 6)):
+            print("Skipping '{0}': need at least Python 3.6".format(modname),
+                  file=sys.stderr)
+            continue
         try:
             loader = importlib.machinery.SourceFileLoader(modname, sourcefile)
             mods.append((loader.load_module(), sourcefile))