bpo-32311: Implement asyncio.create_task() shortcut (#4848)

* Implement functionality
* Add documentation

Lib/test/test_asyncio/test_tasks.py

@@ -2054,6 +2054,43 @@ class BaseTaskTests:
 
         self.assertEqual(self.Task.all_tasks(self.loop), set())
 
+    def test_create_task_with_noncoroutine(self):
+        with self.assertRaisesRegex(TypeError,
+                                    "a coroutine was expected, got 123"):
+            self.new_task(self.loop, 123)
+
+    def test_create_task_with_oldstyle_coroutine(self):
+
+        @asyncio.coroutine
+        def coro():
+            pass
+
+        task = self.new_task(self.loop, coro())
+        self.assertIsInstance(task, self.Task)
+        self.loop.run_until_complete(task)
+
+    def test_create_task_with_async_function(self):
+
+        async def coro():
+            pass
+
+        task = self.new_task(self.loop, coro())
+        self.assertIsInstance(task, self.Task)
+        self.loop.run_until_complete(task)
+
+    def test_bare_create_task(self):
+
+        async def inner():
+            return 1
+
+        async def coro():
+            task = asyncio.create_task(inner())
+            self.assertIsInstance(task, self.Task)
+            ret = await task
+            self.assertEqual(1, ret)
+
+        self.loop.run_until_complete(coro())
+
 
 def add_subclass_tests(cls):
     BaseTask = cls.Task

Lib/test/test_asyncio/utils.py

@@ -28,6 +28,7 @@ except ImportError:  # pragma: no cover
 
 from asyncio import base_events
 from asyncio import events
+from asyncio import format_helpers
 from asyncio import futures
 from asyncio import tasks
 from asyncio.log import logger
@@ -429,7 +430,7 @@ class MockPattern(str):
 
 
 def get_function_source(func):
-    source = events._get_function_source(func)
+    source = format_helpers._get_function_source(func)
     if source is None:
         raise ValueError("unable to get the source of %r" % (func,))
     return source