Improve server functional tests

Patch set [1] fixed timing issues related to the server functional
tests. As part of the review, additional enhancements were
suggested. This patch set provides those enhancements. In particular,
the functional tests will now check for the cirros256 flavor and
the cirros-*-uec image.

[1] https://review.openstack.org/#/c/313870/

Change-Id: I7fe18e26b3d09db92bbe669ffafcd16618cae383

functional/tests/compute/v2/test_server.py

@@ -23,19 +23,27 @@ class ServerTests(test.TestCase):
 
     @classmethod
     def get_flavor(cls):
-        # NOTE(rtheis): Get m1.tiny flavor since functional tests may
-        # create other flavors.
-        raw_output = cls.openstack('flavor show m1.tiny -c id -f value')
-        return raw_output.strip('\n')
+        # NOTE(rtheis): Get cirros256 or m1.tiny flavors since functional
+        # tests may create other flavors.
+        flavors = cls.openstack('flavor list -c Name -f value').split('\n')
+        server_flavor = None
+        for flavor in flavors:
+            if flavor in ['m1.tiny', 'cirros256']:
+                server_flavor = flavor
+                break
+        return server_flavor
 
     @classmethod
     def get_image(cls):
-        # NOTE(rtheis): Get public images since functional tests may
-        # create private images.
-        raw_output = cls.openstack('image list --public -f value -c ID')
-        ray = raw_output.split('\n')
-        idx = int(len(ray) / 2)
-        return ray[idx]
+        # NOTE(rtheis): Get cirros image since functional tests may
+        # create other images.
+        images = cls.openstack('image list -c Name -f value').split('\n')
+        server_image = None
+        for image in images:
+            if image.startswith('cirros-') and image.endswith('-uec'):
+                server_image = image
+                break
+        return server_image
 
     @classmethod
     def get_network(cls):