Test that we're not leaking a request context in the testsuite, fixed a leak

tests/flask_tests.py

@@ -96,7 +96,15 @@ def emits_module_deprecation_warning(f):
 
 
 class FlaskTestCase(unittest.TestCase):
-    pass
+
+    def ensure_clean_request_context(self):
+        # make sure we're not leaking a request context since we are
+        # testing flask internally in debug mode in a few cases
+        self.assertEqual(flask._request_ctx_stack.top, None)
+
+    def tearDown(self):
+        unittest.TestCase.tearDown(self)
+        self.ensure_clean_request_context()
 
 
 class ContextTestCase(FlaskTestCase):
@@ -1881,8 +1889,8 @@ class LoggingTestCase(FlaskTestCase):
         @app.route('/exc')
         def exc():
             1/0
-        c = app.test_client()
 
+        with app.test_client() as c:
             with catch_stderr() as err:
                 c.get('/')
                 out = err.getvalue()