Issue #29198: add AsyncGenerator (Jelle Zijlstra) (3.6->3.7)

1 files changed, 42 insertions, 0 deletions

diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 44712b699b..9ab42a3f6e 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -1735,6 +1735,23 @@ class CollectionsAbcTests(BaseTestCase):
         with self.assertRaises(TypeError):
             typing.Generator[int, int, int]()
 
+    @skipUnless(PY36, 'Python 3.6 required')
+    def test_async_generator(self):
+        ns = {}
+        exec("async def f():\n"
+            "    yield 42\n", globals(), ns)
+        g = ns['f']()
+        self.assertIsSubclass(type(g), typing.AsyncGenerator)
+
+    @skipUnless(PY36, 'Python 3.6 required')
+    def test_no_async_generator_instantiation(self):
+        with self.assertRaises(TypeError):
+            typing.AsyncGenerator()
+        with self.assertRaises(TypeError):
+            typing.AsyncGenerator[T, T]()
+        with self.assertRaises(TypeError):
+            typing.AsyncGenerator[int, int]()
+
     def test_subclassing(self):
 
         class MMA(typing.MutableMapping):
@@ -1804,6 +1821,31 @@ class CollectionsAbcTests(BaseTestCase):
         self.assertIsSubclass(G, collections.Iterable)
         self.assertNotIsSubclass(type(g), G)
 
+    @skipUnless(PY36, 'Python 3.6 required')
+    def test_subclassing_async_generator(self):
+        class G(typing.AsyncGenerator[int, int]):
+            def asend(self, value):
+                pass
+            def athrow(self, typ, val=None, tb=None):
+                pass
+
+        ns = {}
+        exec('async def g(): yield 0', globals(), ns)
+        g = ns['g']
+        self.assertIsSubclass(G, typing.AsyncGenerator)
+        self.assertIsSubclass(G, typing.AsyncIterable)
+        self.assertIsSubclass(G, collections.AsyncGenerator)
+        self.assertIsSubclass(G, collections.AsyncIterable)
+        self.assertNotIsSubclass(type(g), G)
+
+        instance = G()
+        self.assertIsInstance(instance, typing.AsyncGenerator)
+        self.assertIsInstance(instance, typing.AsyncIterable)
+        self.assertIsInstance(instance, collections.AsyncGenerator)
+        self.assertIsInstance(instance, collections.AsyncIterable)
+        self.assertNotIsInstance(type(g), G)
+        self.assertNotIsInstance(g, G)
+
     def test_subclassing_subclasshook(self):
 
         class Base(typing.Iterable):