functional: Make '_wait_for_state_change' behave consistently

Both 'ServersTestBase' and 'InstanceHelperMixin' provide implementations
of '_wait_for_state_change' but they behave differently. The former
waits for an instance to transition *from* the provided state, while the
latter, somewhat more sanely, waits for the transition *to* the provided
state. Switch to using the latter everywhere and make the necessary
changes. Due to class hierarchies, we end up with two nearly identical
implementations but these will be merged in a future change.

Change-Id: I80cdc0a33ec27b1389130c22f9c3a8ff69f6b1a0
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>

1 files changed, 4 insertions, 8 deletions

diff --git a/nova/tests/functional/test_images.py b/nova/tests/functional/test_images.py
index 7c3ec85748..0edb3f29cb 100644
--- a/nova/tests/functional/test_images.py
+++ b/nova/tests/functional/test_images.py
@@ -24,14 +24,13 @@ class ImagesTest(test_servers.ServersTestBase):
         server = self._build_minimal_create_server_request()
         created_server = self.api.post_server({"server": server})
         server_id = created_server['id']
-        found_server = self._wait_for_state_change(created_server, 'BUILD')
-        self.assertEqual('ACTIVE', found_server['status'])
+        found_server = self._wait_for_state_change(created_server, 'ACTIVE')
 
         # Create image
         name = 'Snapshot 1'
         self.api.post_server_action(
             server_id, {'createImage': {'name': name}})
-        self.assertEqual('ACTIVE', found_server['status'])
+
         # Confirm that the image was created
         images = self.api.get_images(detail=False)
         image_map = {image['name']: image for image in images}
@@ -41,8 +40,7 @@ class ImagesTest(test_servers.ServersTestBase):
         # Change server status from ACTIVE to SHELVED for negative test
         self.flags(shelved_offload_time = -1)
         self.api.post_server_action(server_id, {'shelve': {}})
-        found_server = self._wait_for_state_change(found_server, 'ACTIVE')
-        self.assertEqual('SHELVED', found_server['status'])
+        found_server = self._wait_for_state_change(found_server, 'SHELVED')
 
         # Create image in SHELVED (not ACTIVE, etc.)
         name = 'Snapshot 2'
@@ -51,7 +49,6 @@ class ImagesTest(test_servers.ServersTestBase):
                                server_id,
                                {'createImage': {'name': name}})
         self.assertEqual(409, ex.response.status_code)
-        self.assertEqual('SHELVED', found_server['status'])
 
         # Confirm that the image was not created
         images = self.api.get_images(detail=False)
@@ -71,8 +68,7 @@ class ImagesTest(test_servers.ServersTestBase):
         # Create a server using the tenant user project.
         server = self._build_minimal_create_server_request()
         server = self.api.post_server({"server": server})
-        server = self._wait_for_state_change(server, 'BUILD')
-        self.assertEqual('ACTIVE', server['status'])
+        server = self._wait_for_state_change(server, 'ACTIVE')
 
         # Create an admin API fixture with a unique project ID.
         admin_api = self.useFixture(