Make tests nicer

tests/test_not_implemented.py

@@ -25,18 +25,11 @@ def test_rejecting_coroutine_functions():
     if sys.version_info[:2] <= (3, 4):
         pytest.skip()
 
-    class Thing:
-        pass
-
-    thing = Thing()
-
     code = textwrap.dedent('''
     async def foo(x):
         return 'lol'
-    thing.foo = foo
     ''')
-    exec(code)
-    foo = thing.foo
+    exec(code, globals())
 
     assert pycompat.iscoroutinefunction(foo)
     assert not pycompat.isasyncgenfunction(foo)
@@ -48,18 +41,11 @@ def test_rejecting_async_generator_functions():
     if sys.version_info[:2] <= (3, 6):
         pytest.skip()
 
-    class Thing:
-        pass
-
-    thing = Thing()
-
     code = textwrap.dedent('''
     async def foo(x):
         yield 'lol'
-    thing.foo = foo
     ''')
-    exec(code)
-    foo = thing.foo
+    exec(code, globals())
 
     assert not pycompat.iscoroutinefunction(foo)
     assert pycompat.isasyncgenfunction(foo)