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

4 files changed, 28 insertions, 16 deletions

diff --git a/openstackclient/tests/functional/volume/v2/common.py b/openstackclient/tests/functional/volume/v2/common.py
index 1d14719f..38176714 100644
--- a/openstackclient/tests/functional/volume/v2/common.py
+++ b/openstackclient/tests/functional/volume/v2/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'] = '2'
+    def setUp(self):
+        super(BaseVolumeTests, self).setUp()
+        ver_fixture = fixtures.EnvironmentVariable(
+            'OS_VOLUME_API_VERSION', '2'
+        )
+        self.useFixture(ver_fixture)
diff --git a/openstackclient/tests/functional/volume/v2/test_snapshot.py b/openstackclient/tests/functional/volume/v2/test_snapshot.py
index 2fff43c8..ba6b2c28 100644
--- a/openstackclient/tests/functional/volume/v2/test_snapshot.py
+++ b/openstackclient/tests/functional/volume/v2/test_snapshot.py
@@ -35,10 +35,13 @@ class VolumeSnapshotTests(common.BaseVolumeTests):
 
     @classmethod
     def tearDownClass(cls):
-        cls.wait_for_status('volume', cls.VOLLY, 'available')
-        raw_output = cls.openstack(
-            'volume delete --force ' + cls.VOLLY)
-        cls.assertOutput('', raw_output)
+        try:
+            cls.wait_for_status('volume', cls.VOLLY, 'available')
+            raw_output = cls.openstack(
+                'volume delete --force ' + cls.VOLLY)
+            cls.assertOutput('', raw_output)
+        finally:
+            super(VolumeSnapshotTests, cls).tearDownClass()
 
     def test_volume_snapshot__delete(self):
         """Test create, delete multiple"""
diff --git a/openstackclient/tests/functional/volume/v2/test_transfer_request.py b/openstackclient/tests/functional/volume/v2/test_transfer_request.py
index e9c2236b..33495af6 100644
--- a/openstackclient/tests/functional/volume/v2/test_transfer_request.py
+++ b/openstackclient/tests/functional/volume/v2/test_transfer_request.py
@@ -38,12 +38,15 @@ class TransferRequestTests(common.BaseVolumeTests):
 
     @classmethod
     def tearDownClass(cls):
-        raw_output_transfer = cls.openstack(
-            'volume transfer request delete ' + cls.NAME)
-        raw_output_volume = cls.openstack(
-            'volume delete ' + cls.VOLUME_NAME)
-        cls.assertOutput('', raw_output_transfer)
-        cls.assertOutput('', raw_output_volume)
+        try:
+            raw_output_transfer = cls.openstack(
+                'volume transfer request delete ' + cls.NAME)
+            raw_output_volume = cls.openstack(
+                'volume delete ' + cls.VOLUME_NAME)
+            cls.assertOutput('', raw_output_transfer)
+            cls.assertOutput('', raw_output_volume)
+        finally:
+            super(TransferRequestTests, cls).tearDownClass()
 
     def test_volume_transfer_request_accept(self):
         volume_name = uuid.uuid4().hex
diff --git a/openstackclient/tests/functional/volume/v2/test_volume_type.py b/openstackclient/tests/functional/volume/v2/test_volume_type.py
index 11acf2f8..99630e6b 100644
--- a/openstackclient/tests/functional/volume/v2/test_volume_type.py
+++ b/openstackclient/tests/functional/volume/v2/test_volume_type.py
@@ -31,8 +31,11 @@ class VolumeTypeTests(common.BaseVolumeTests):
 
     @classmethod
     def tearDownClass(cls):
-        raw_output = cls.openstack('volume type delete ' + cls.NAME)
-        cls.assertOutput('', raw_output)
+        try:
+            raw_output = cls.openstack('volume type delete ' + cls.NAME)
+            cls.assertOutput('', raw_output)
+        finally:
+            super(VolumeTypeTests, cls).tearDownClass()
 
     def test_volume_type_list(self):
         cmd_output = json.loads(self.openstack('volume type list -f json'))