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, 4 insertions, 2 deletions

diff --git a/openstackclient/tests/image/v2/fakes.py b/openstackclient/tests/image/v2/fakes.py
index 3555d2d4..f90d846d 100644
--- a/openstackclient/tests/image/v2/fakes.py
+++ b/openstackclient/tests/image/v2/fakes.py
@@ -181,7 +181,7 @@ class FakeImage(object):
     """
 
     @staticmethod
-    def create_one_image(attrs={}):
+    def create_one_image(attrs=None):
         """Create a fake image.
 
         :param Dictionary attrs:
@@ -190,6 +190,8 @@ class FakeImage(object):
             A FakeResource object with id, name, owner, protected,
             visibility and tags attrs
         """
+        attrs = attrs or {}
+
         # Set default attribute
         image_info = {
             'id': 'image-id' + uuid.uuid4().hex,
@@ -210,7 +212,7 @@ class FakeImage(object):
         return image
 
     @staticmethod
-    def create_images(attrs={}, count=2):
+    def create_images(attrs=None, count=2):
         """Create multiple fake images.
 
         :param Dictionary attrs: