Clean up the changes of os.environ in functional tests

Use fixtures to restore the API version changes of os.environ
in each functional tests, aims to avoid the following test cases
failing in unexpected context.

And make sure setUpClass/tearDownClass call super class's
corresponding methods first.

Change-Id: Ie248fe9d3a9e25f1b076c9f2c363200f29a83817
Closes-Bug: #1696080

6 files changed, 17 insertions, 40 deletions

diff --git a/openstackclient/tests/functional/volume/v3/common.py b/openstackclient/tests/functional/volume/v3/common.py
index bc8befa6..a710a683 100644
--- a/openstackclient/tests/functional/volume/v3/common.py
+++ b/openstackclient/tests/functional/volume/v3/common.py
@@ -10,7 +10,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import os
+import fixtures
 
 from openstackclient.tests.functional.volume import base
 
@@ -18,6 +18,9 @@ from openstackclient.tests.functional.volume import base
 class BaseVolumeTests(base.BaseVolumeTests):
     """Base class for Volume functional tests. """
 
-    @classmethod
-    def setUpClass(cls):
-        os.environ['OS_VOLUME_API_VERSION'] = '3'
+    def setUp(self):
+        super(BaseVolumeTests, self).setUp()
+        ver_fixture = fixtures.EnvironmentVariable(
+            'OS_VOLUME_API_VERSION', '3'
+        )
+        self.useFixture(ver_fixture)
diff --git a/openstackclient/tests/functional/volume/v3/test_qos.py b/openstackclient/tests/functional/volume/v3/test_qos.py
index a7af3c5b..a6290fc5 100644
--- a/openstackclient/tests/functional/volume/v3/test_qos.py
+++ b/openstackclient/tests/functional/volume/v3/test_qos.py
@@ -10,15 +10,9 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import os
-
 from openstackclient.tests.functional.volume.v2 import test_qos as v2
+from openstackclient.tests.functional.volume.v3 import common
 
 
-class QosTests(v2.QosTests):
+class QosTests(common.BaseVolumeTests, v2.QosTests):
     """Functional tests for volume qos. """
-
-    @classmethod
-    def setUpClass(cls):
-        super(QosTests, cls).setUpClass()
-        os.environ['OS_VOLUME_API_VERSION'] = '3'
diff --git a/openstackclient/tests/functional/volume/v3/test_snapshot.py b/openstackclient/tests/functional/volume/v3/test_snapshot.py
index bf05b9de..38e0563a 100644
--- a/openstackclient/tests/functional/volume/v3/test_snapshot.py
+++ b/openstackclient/tests/functional/volume/v3/test_snapshot.py
@@ -11,13 +11,8 @@
 #    under the License.
 
 from openstackclient.tests.functional.volume.v2 import test_snapshot as v2
-import os
+from openstackclient.tests.functional.volume.v3 import common
 
 
-class VolumeSnapshotTests(v2.VolumeSnapshotTests):
+class VolumeSnapshotTests(common.BaseVolumeTests, v2.VolumeSnapshotTests):
     """Functional tests for volume snapshot. """
-
-    @classmethod
-    def setUpClass(cls):
-        super(VolumeSnapshotTests, cls).setUpClass()
-        os.environ['OS_VOLUME_API_VERSION'] = '3'
diff --git a/openstackclient/tests/functional/volume/v3/test_transfer_request.py b/openstackclient/tests/functional/volume/v3/test_transfer_request.py
index 7b54dd20..b3253237 100644
--- a/openstackclient/tests/functional/volume/v3/test_transfer_request.py
+++ b/openstackclient/tests/functional/volume/v3/test_transfer_request.py
@@ -12,13 +12,8 @@
 
 from openstackclient.tests.functional.volume.v2 import test_transfer_request \
     as v2
-import os
+from openstackclient.tests.functional.volume.v3 import common
 
 
-class TransferRequestTests(v2.TransferRequestTests):
+class TransferRequestTests(common.BaseVolumeTests, v2.TransferRequestTests):
     """Functional tests for transfer request. """
-
-    @classmethod
-    def setUpClass(cls):
-        super(TransferRequestTests, cls).setUpClass()
-        os.environ['OS_VOLUME_API_VERSION'] = '3'
diff --git a/openstackclient/tests/functional/volume/v3/test_volume.py b/openstackclient/tests/functional/volume/v3/test_volume.py
index 333826d8..283b830f 100644
--- a/openstackclient/tests/functional/volume/v3/test_volume.py
+++ b/openstackclient/tests/functional/volume/v3/test_volume.py
@@ -11,13 +11,8 @@
 #    under the License.
 
 from openstackclient.tests.functional.volume.v2 import test_volume as v2
-import os
+from openstackclient.tests.functional.volume.v3 import common
 
 
-class VolumeTests(v2.VolumeTests):
+class VolumeTests(common.BaseVolumeTests, v2.VolumeTests):
     """Functional tests for volume. """
-
-    @classmethod
-    def setUpClass(cls):
-        super(VolumeTests, cls).setUpClass()
-        os.environ['OS_VOLUME_API_VERSION'] = '3'
diff --git a/openstackclient/tests/functional/volume/v3/test_volume_type.py b/openstackclient/tests/functional/volume/v3/test_volume_type.py
index f10e64b4..eb66515e 100644
--- a/openstackclient/tests/functional/volume/v3/test_volume_type.py
+++ b/openstackclient/tests/functional/volume/v3/test_volume_type.py
@@ -11,13 +11,8 @@
 #    under the License.
 
 from openstackclient.tests.functional.volume.v2 import test_volume_type as v2
-import os
+from openstackclient.tests.functional.volume.v3 import common
 
 
-class VolumeTypeTests(v2.VolumeTypeTests):
+class VolumeTypeTests(common.BaseVolumeTests, v2.VolumeTypeTests):
     """Functional tests for volume type. """
-
-    @classmethod
-    def setUpClass(cls):
-        super(VolumeTypeTests, cls).setUpClass()
-        os.environ['OS_VOLUME_API_VERSION'] = '3'