Add APIMicroversionFixture to library interface

APIMicroversionFixture is used to set the microversion on
service clients which will take care of reseting the microversion.

This interface has been added to set the microversion on all supported
service clients which use microverison. User can set multiple
service microversion all together.

Using the new interface in compute tests to make sure it is all
working in serial and parallel testing.

Change-Id: I6ed41b02041d38c2c92c58b0d3dd6613d03da3f7
diff --git a/releasenotes/notes/lib_api_microversion_fixture-f52308fc6b6b89f2.yaml b/releasenotes/notes/lib_api_microversion_fixture-f52308fc6b6b89f2.yaml
new file mode 100644
index 0000000..d707fc7
--- /dev/null
+++ b/releasenotes/notes/lib_api_microversion_fixture-f52308fc6b6b89f2.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    New library interface to set the API microversion on Service Clients.
+    ``APIMicroversionFixture,`` can be used to set the API microversion
+    on multiple services. This Fixture will take care of reseting the service
+    microversion to None once test is finished.
diff --git a/tempest/api/compute/base.py b/tempest/api/compute/base.py
index 624a99e..e71e642 100644
--- a/tempest/api/compute/base.py
+++ b/tempest/api/compute/base.py
@@ -17,11 +17,11 @@
 
 from oslo_log import log as logging
 
-from tempest.api.compute import api_microversion_fixture
 from tempest.common import compute
 from tempest.common import waiters
 from tempest import config
 from tempest import exceptions
+from tempest.lib.common import api_microversion_fixture
 from tempest.lib.common import api_version_request
 from tempest.lib.common import api_version_utils
 from tempest.lib.common.utils import data_utils
@@ -470,7 +470,7 @@
     def setUp(self):
         super(BaseV2ComputeTest, self).setUp()
         self.useFixture(api_microversion_fixture.APIMicroversionFixture(
-            self.request_microversion))
+            compute_microversion=self.request_microversion))
 
     @classmethod
     def create_volume(cls, image_ref=None, **kwargs):
diff --git a/tempest/lib/common/api_microversion_fixture.py b/tempest/lib/common/api_microversion_fixture.py
new file mode 100644
index 0000000..3837138
--- /dev/null
+++ b/tempest/lib/common/api_microversion_fixture.py
@@ -0,0 +1,82 @@
+# Copyright 2019 NEC Corporation.  All rights reserved.
+#
+# 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 tempest.lib.services.compute import base_compute_client
+from tempest.lib.services.placement import base_placement_client
+from tempest.lib.services.volume import base_client as base_volume_client
+
+
+class APIMicroversionFixture(fixtures.Fixture):
+    """API Microversion Fixture to set service microversion.
+
+    This class provides the fixture to set and reset the microversion
+    on service client. Service client has global variable to set the
+    microversion for that service API request.
+    For example: base_compute_client.COMPUTE_MICROVERSION
+    Global variable is always risky to set directly which can affect the
+    other test's API request also. This class provides a way to reset the
+    service microversion once test finish the API request.
+    This class can be used with useFixture: Example::
+
+        def setUp(self):
+            super(BaseV2ComputeTest, self).setUp()
+            self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+                compute_microversion=self.compute_request_microversion))
+
+    Or you can set microversion on multiple services together::
+
+        def setUp(self):
+            super(ScenarioTest, self).setUp()
+            self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+                compute_microversion=self.compute_request_microversion,
+                volume_microversion=self.volume_request_microversion))
+
+    Current supported services:
+    - Compute
+    - Volume
+    - Placement
+
+    :param str compute_microversion: microvesion to be set on compute
+                                     service clients
+    :param str volume_microversion: microvesion to be set on volume
+                                    service clients
+    :param str placement_microversion: microvesion to be set on placement
+                                       service clients
+    """
+
+    def __init__(self, compute_microversion=None, volume_microversion=None,
+                 placement_microversion=None):
+        self.compute_microversion = compute_microversion
+        self.volume_microversion = volume_microversion
+        self.placement_microversion = placement_microversion
+
+    def _setUp(self):
+        super(APIMicroversionFixture, self)._setUp()
+        if self.compute_microversion:
+            base_compute_client.COMPUTE_MICROVERSION = (
+                self.compute_microversion)
+        if self.volume_microversion:
+            base_volume_client.VOLUME_MICROVERSION = self.volume_microversion
+        if self.placement_microversion:
+            base_placement_client.PLACEMENT_MICROVERSION = (
+                self.placement_microversion)
+
+        self.addCleanup(self._reset_microversion)
+
+    def _reset_microversion(self):
+        base_compute_client.COMPUTE_MICROVERSION = None
+        base_volume_client.VOLUME_MICROVERSION = None
+        base_placement_client.PLACEMENT_MICROVERSION = None
diff --git a/tempest/tests/lib/test_api_microversion_fixture.py b/tempest/tests/lib/test_api_microversion_fixture.py
new file mode 100644
index 0000000..ad98ed0
--- /dev/null
+++ b/tempest/tests/lib/test_api_microversion_fixture.py
@@ -0,0 +1,58 @@
+# Copyright 2019 NEC Corporation.
+#
+#    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 tempest.lib.common import api_microversion_fixture
+from tempest.lib.services.compute import base_compute_client
+from tempest.lib.services.placement import base_placement_client
+from tempest.lib.services.volume import base_client
+from tempest.tests import base
+
+
+class TestAPIMicroversionFixture(base.TestCase):
+    def setUp(self):
+        super(TestAPIMicroversionFixture, self).setUp()
+        # Verify that all the microversion are reset back to None
+        # by Fixture.
+        self.assertIsNone(base_compute_client.COMPUTE_MICROVERSION)
+        self.assertIsNone(base_client.VOLUME_MICROVERSION)
+        self.assertIsNone(base_placement_client.PLACEMENT_MICROVERSION)
+
+    def test_compute_microversion(self):
+        self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+            compute_microversion='2.10'))
+        self.assertEqual('2.10', base_compute_client.COMPUTE_MICROVERSION)
+        self.assertIsNone(base_client.VOLUME_MICROVERSION)
+        self.assertIsNone(base_placement_client.PLACEMENT_MICROVERSION)
+
+    def test_volume_microversion(self):
+        self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+            volume_microversion='3.10'))
+        self.assertIsNone(base_compute_client.COMPUTE_MICROVERSION)
+        self.assertEqual('3.10', base_client.VOLUME_MICROVERSION)
+        self.assertIsNone(base_placement_client.PLACEMENT_MICROVERSION)
+
+    def test_placement_microversion(self):
+        self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+            placement_microversion='1.10'))
+        self.assertIsNone(base_compute_client.COMPUTE_MICROVERSION)
+        self.assertIsNone(base_client.VOLUME_MICROVERSION)
+        self.assertEqual('1.10', base_placement_client.PLACEMENT_MICROVERSION)
+
+    def test_multiple_service_microversion(self):
+        self.useFixture(api_microversion_fixture.APIMicroversionFixture(
+            compute_microversion='2.10', volume_microversion='3.10',
+            placement_microversion='1.10'))
+        self.assertEqual('2.10', base_compute_client.COMPUTE_MICROVERSION)
+        self.assertEqual('3.10', base_client.VOLUME_MICROVERSION)
+        self.assertEqual('1.10', base_placement_client.PLACEMENT_MICROVERSION)