Fix mutable default arguments in tests

Python’s default arguments are evaluated only once
when the function is defined, not each time the
function is called. This means that if you use a
mutable default argument (like list and dict) and
mutate it, you will and have mutated that object
for all future calls to the function as well.

More details about this wrong usage here:
http://docs.python-guide.org/en/latest/writing/gotchas/#mutable-default-arguments

In unit tests, most FakeXXX classes' methods take
mutable arguments with default values [] or {}.
We should change them to None.

Change-Id: Iea833b66aa1379829511ad5c6d4432b72f3488e2
Closed-bug: #1550320

1 files changed, 8 insertions, 4 deletions

diff --git a/openstackclient/tests/volume/v2/fakes.py b/openstackclient/tests/volume/v2/fakes.py
index 6e631c41..b7994b5f 100644
--- a/openstackclient/tests/volume/v2/fakes.py
+++ b/openstackclient/tests/volume/v2/fakes.py
@@ -281,7 +281,7 @@ class FakeVolume(object):
     """
 
     @staticmethod
-    def create_one_volume(attrs={}):
+    def create_one_volume(attrs=None):
         """Create a fake volume.
 
         :param Dictionary attrs:
@@ -289,6 +289,8 @@ class FakeVolume(object):
         :retrun:
             A FakeResource object with id, name, status, etc.
         """
+        attrs = attrs or {}
+
         # Set default attribute
         volume_info = {
             'id': 'volume-id' + uuid.uuid4().hex,
@@ -320,7 +322,7 @@ class FakeVolume(object):
         return volume
 
     @staticmethod
-    def create_volumes(attrs={}, count=2):
+    def create_volumes(attrs=None, count=2):
         """Create multiple fake volumes.
 
         :param Dictionary attrs:
@@ -361,7 +363,7 @@ class FakeAvailabilityZone(object):
     """Fake one or more volume availability zones (AZs)."""
 
     @staticmethod
-    def create_one_availability_zone(attrs={}):
+    def create_one_availability_zone(attrs=None):
         """Create a fake AZ.
 
         :param Dictionary attrs:
@@ -369,6 +371,8 @@ class FakeAvailabilityZone(object):
         :return:
             A FakeResource object with zoneName, zoneState, etc.
         """
+        attrs = attrs or {}
+
         # Set default attributes.
         availability_zone = {
             'zoneName': uuid.uuid4().hex,
@@ -384,7 +388,7 @@ class FakeAvailabilityZone(object):
         return availability_zone
 
     @staticmethod
-    def create_availability_zones(attrs={}, count=2):
+    def create_availability_zones(attrs=None, count=2):
         """Create multiple fake AZs.
 
         :param Dictionary attrs: