bpo-46994: Accept explicit contextvars.Context in asyncio create_task() API (GH-31837)

2 files changed, 104 insertions, 2 deletions

diff --git a/Lib/test/test_asyncio/test_taskgroups.py b/Lib/test/test_asyncio/test_taskgroups.py
index df51528..dea5d6d 100644
--- a/Lib/test/test_asyncio/test_taskgroups.py
+++ b/Lib/test/test_asyncio/test_taskgroups.py
@@ -2,6 +2,7 @@
 
 
 import asyncio
+import contextvars
 
 from asyncio import taskgroups
 import unittest
@@ -708,6 +709,23 @@ class TestTaskGroup(unittest.IsolatedAsyncioTestCase):
             t = g.create_task(coro(), name="yolo")
             self.assertEqual(t.get_name(), "yolo")
 
+    async def test_taskgroup_task_context(self):
+        cvar = contextvars.ContextVar('cvar')
+
+        async def coro(val):
+            await asyncio.sleep(0)
+            cvar.set(val)
+
+        async with taskgroups.TaskGroup() as g:
+            ctx = contextvars.copy_context()
+            self.assertIsNone(ctx.get(cvar))
+            t1 = g.create_task(coro(1), context=ctx)
+            await t1
+            self.assertEqual(1, ctx.get(cvar))
+            t2 = g.create_task(coro(2), context=ctx)
+            await t2
+            self.assertEqual(2, ctx.get(cvar))
+
 
 if __name__ == "__main__":
     unittest.main()
diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py
index 95fabf7..b6ef627 100644
--- a/Lib/test/test_asyncio/test_tasks.py
+++ b/Lib/test/test_asyncio/test_tasks.py
@@ -95,8 +95,8 @@ class BaseTaskTests:
     Task = None
     Future = None
 
-    def new_task(self, loop, coro, name='TestTask'):
-        return self.__class__.Task(coro, loop=loop, name=name)
+    def new_task(self, loop, coro, name='TestTask', context=None):
+        return self.__class__.Task(coro, loop=loop, name=name, context=context)
 
     def new_future(self, loop):
         return self.__class__.Future(loop=loop)
@@ -2527,6 +2527,90 @@ class BaseTaskTests:
 
         self.assertEqual(cvar.get(), -1)
 
+    def test_context_4(self):
+        cvar = contextvars.ContextVar('cvar')
+
+        async def coro(val):
+            await asyncio.sleep(0)
+            cvar.set(val)
+
+        async def main():
+            ret = []
+            ctx = contextvars.copy_context()
+            ret.append(ctx.get(cvar))
+            t1 = self.new_task(loop, coro(1), context=ctx)
+            await t1
+            ret.append(ctx.get(cvar))
+            t2 = self.new_task(loop, coro(2), context=ctx)
+            await t2
+            ret.append(ctx.get(cvar))
+            return ret
+
+        loop = asyncio.new_event_loop()
+        try:
+            task = self.new_task(loop, main())
+            ret = loop.run_until_complete(task)
+        finally:
+            loop.close()
+
+        self.assertEqual([None, 1, 2], ret)
+
+    def test_context_5(self):
+        cvar = contextvars.ContextVar('cvar')
+
+        async def coro(val):
+            await asyncio.sleep(0)
+            cvar.set(val)
+
+        async def main():
+            ret = []
+            ctx = contextvars.copy_context()
+            ret.append(ctx.get(cvar))
+            t1 = asyncio.create_task(coro(1), context=ctx)
+            await t1
+            ret.append(ctx.get(cvar))
+            t2 = asyncio.create_task(coro(2), context=ctx)
+            await t2
+            ret.append(ctx.get(cvar))
+            return ret
+
+        loop = asyncio.new_event_loop()
+        try:
+            task = self.new_task(loop, main())
+            ret = loop.run_until_complete(task)
+        finally:
+            loop.close()
+
+        self.assertEqual([None, 1, 2], ret)
+
+    def test_context_6(self):
+        cvar = contextvars.ContextVar('cvar')
+
+        async def coro(val):
+            await asyncio.sleep(0)
+            cvar.set(val)
+
+        async def main():
+            ret = []
+            ctx = contextvars.copy_context()
+            ret.append(ctx.get(cvar))
+            t1 = loop.create_task(coro(1), context=ctx)
+            await t1
+            ret.append(ctx.get(cvar))
+            t2 = loop.create_task(coro(2), context=ctx)
+            await t2
+            ret.append(ctx.get(cvar))
+            return ret
+
+        loop = asyncio.new_event_loop()
+        try:
+            task = loop.create_task(main())
+            ret = loop.run_until_complete(task)
+        finally:
+            loop.close()
+
+        self.assertEqual([None, 1, 2], ret)
+
     def test_get_coro(self):
         loop = asyncio.new_event_loop()
         coro = coroutine_function()