Add a regression test for 5.12 compute API issue

In I147bf4d95e6d86ff1f967a8ce37260730f21d236 we wrote a breaking RPC change
for the 5.12 version as the accel_uuids parameter is not optional.

Adding a regression test to check the issue.

Change-Id: I1f3914e16294c99a625b3984ca0098d835cd9b92
Related-Bug: #1902925

nova/tests/functional/regressions/test_bug_1902925.py

@@ -0,0 +1,52 @@
+# 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 nova.tests.functional.api import client
+from nova.tests.functional import integrated_helpers
+from nova.tests.unit import cast_as_call
+
+
+class ComputeVersion5xPinnedRpcTests(integrated_helpers._IntegratedTestBase):
+
+    compute_driver = 'fake.MediumFakeDriver'
+    ADMIN_API = True
+    api_major_version = 'v2.1'
+    microversion = 'latest'
+
+    def setUp(self):
+        super(ComputeVersion5xPinnedRpcTests, self).setUp()
+        self.useFixture(cast_as_call.CastAsCall(self))
+
+        self.compute1 = self._start_compute(host='host1')
+
+    def _test_rebuild_instance_with_compute_rpc_pin(self, version_cap):
+        self.flags(compute=version_cap, group='upgrade_levels')
+
+        server_req = self._build_server(networks='none')
+        server = self.api.post_server({'server': server_req})
+        server = self._wait_for_state_change(server, 'ACTIVE')
+
+        self.api.post_server_action(server['id'], {'rebuild': {
+            'imageRef': '155d900f-4e14-4e4c-a73d-069cbf4541e6'
+        }})
+
+    def test_rebuild_instance_5_0(self):
+        e = self.assertRaises(client.OpenStackApiException,
+            self._test_rebuild_instance_with_compute_rpc_pin, '5.0')
+        self.assertEqual(500, e.response.status_code)
+        # NOTE(sbauza): It provides a TypeError because of 'accel_uuids'
+        # parameter missing
+        # TypeError: rebuild_instance() missing 1 required positional argument:
+        #            'accel_uuids'
+        self.assertIn('TypeError', e.response.text)
+
+    def test_rebuild_instance_5_12(self):
+        self._test_rebuild_instance_with_compute_rpc_pin('5.12')