Add ClearRequestContext fixture

Add a fixture class for use in tests to provide a way to flush the
cached RequestContext without exposing how that is stored.

bp/graduate-oslo-context

Change-Id: I27dd50a61d364e1698823629e2676c10ced50af3

doc/source/api/autoindex.rst

@@ -2,4 +2,5 @@
    :maxdepth: 1
 
    oslo_context.context.rst
+   oslo_context.fixture.rst
    oslo_context.tests.test_context.rst

doc/source/api/oslo_context.fixture.rst

@@ -0,0 +1,7 @@
+The :mod:`oslo_context.fixture` Module
+======================================
+
+.. automodule:: oslo_context.fixture
+  :members:
+  :undoc-members:
+  :show-inheritance:

oslo_context/fixture.py

@@ -0,0 +1,30 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import fixtures
+
+from oslo_context import context
+
+
+class ClearRequestContext(fixtures.Fixture):
+    """Clears any cached RequestContext at the end of a test case."""
+
+    def setUp(self):
+        super(ClearRequestContext, self).setUp()
+        self.addCleanup(self._remove_cached_context)
+
+    def _remove_cached_context(self):
+        """Remove the thread-local context stored in the module."""
+        try:
+            del context._request_store.context
+        except AttributeError:
+            pass

oslo_context/tests/test_context.py

@@ -16,20 +16,14 @@
 from oslotest import base as test_base
 
 from oslo_context import context
+from oslo_context import fixture
 
 
 class ContextTest(test_base.BaseTestCase):
 
     def setUp(self):
         super(ContextTest, self).setUp()
-        self.addCleanup(self._remove_cached_context)
-
-    def _remove_cached_context(self):
-        """Remove the thread-local context stored in the module."""
-        try:
-            del context._request_store.context
-        except AttributeError:
-            pass
+        self.useFixture(fixture.ClearRequestContext())
 
     def test_context(self):
         ctx = context.RequestContext()
@@ -57,7 +51,6 @@ class ContextTest(test_base.BaseTestCase):
 
     def test_store_current(self):
         # By default a new context is stored.
-        self._remove_cached_context()
         ctx = context.RequestContext()
         self.assertIs(context.get_current(), ctx)
 

oslo_context/tests/test_fixture.py

@@ -0,0 +1,30 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslotest import base as test_base
+
+from oslo_context import context
+from oslo_context import fixture
+
+
+class ClearRequestContextTest(test_base.BaseTestCase):
+
+    # def setUp(self):
+    #     super(ContextTest, self).setUp()
+    #     self.useFixture(fixture.ClearRequestContext())
+
+    def test_store_current(self):
+        # By default a new context is stored.
+        ctx = context.RequestContext()
+        self.assertIs(context.get_current(), ctx)
+        fixture.ClearRequestContext()._remove_cached_context()
+        self.assertIsNone(context.get_current())