assert that deprecation warning is emitted

Lib/test/test_asyncgen.py

@@ -382,8 +382,7 @@ def test_async_gen_3_arg_deprecation_warning(self):
         async def gen():
             yield 123
 
-        with warnings.catch_warnings():
-            warnings.filterwarnings("ignore", category=DeprecationWarning)
+        with self.assertWarns(DeprecationWarning):
             gen().athrow(GeneratorExit, GeneratorExit(), None)
 
     def test_async_gen_api_01(self):

Lib/test/test_asyncio/test_futures.py

@@ -620,6 +620,8 @@ def test_future_stop_iteration_args(self):
     def test_future_iter_throw(self):
         fut = self._new_future(loop=self.loop)
         fi = iter(fut)
+        with self.assertWarns(DeprecationWarning):
+            fi.throw(Exception, Exception("zebra"), None)
         with warnings.catch_warnings():
             warnings.filterwarnings("ignore", category=DeprecationWarning)
             self.assertRaises(TypeError, fi.throw,

Lib/test/test_coroutines.py

@@ -712,6 +712,13 @@ async def foo():
             aw.throw(ZeroDivisionError())
         self.assertEqual(N, 102)
 
+        coro = foo()
+        aw = coro.__await__()
+        next(aw)
+        with self.assertRaises(ZeroDivisionError):
+            with self.assertWarns(DeprecationWarning):
+                aw.throw(ZeroDivisionError, ZeroDivisionError(), None)
+
     def test_func_11(self):
         async def func(): pass
         coro = func()

Lib/test/test_generators.py

@@ -342,6 +342,15 @@ def generator():
         with self.assertRaises(StopIteration):
             gen.throw(E)
 
+    def test_gen_3_arg_deprecation_warning(self):
+        def g():
+            yield 42
+
+        gen = g()
+        with self.assertWarns(DeprecationWarning):
+            with self.assertRaises(TypeError):
+                gen.throw(TypeError, TypeError(24), None)
+
     def test_stopiteration_error(self):
         # See also PEP 479.