Issue #24325, #24400: Add more unittests for types.coroutine; tweak wrapper implementation.

Lib/test/test_asyncio/test_pep492.py

@@ -1,6 +1,7 @@
 """Tests support for new syntax introduced by PEP 492."""
 
 import collections.abc
+import types
 import unittest
 
 from test import support
@@ -164,5 +165,23 @@ class CoroutineTests(BaseTest):
         self.loop.run_until_complete(start())
 
 
+    def test_types_coroutine(self):
+        def gen():
+            yield from ()
+            return 'spam'
+
+        @types.coroutine
+        def func():
+            return gen()
+
+        async def coro():
+            wrapper = func()
+            self.assertIsInstance(wrapper, types._GeneratorWrapper)
+            return await wrapper
+
+        data = self.loop.run_until_complete(coro())
+        self.assertEqual(data, 'spam')
+
+
 if __name__ == '__main__':
     unittest.main()