Python 3: Fix JsonPatch-related issues

In Python 3, the generated JSON patches have a different representation than
those generated with Python 2. For instance, the patch generated in
test_patch_should_replace_missing_core_properties() is:

    '[{"op": "replace", "value": "red", "path": "/color"}]'

in Python 2, but:

    '[{"path": "/color", "value": "red", "op": "replace"}]'

in Python 3. Therefore, the comparison fails, and the test fail. We fix the
tests by comparing JsonPatch objects rather than strings.

Closes-Bug: #1281374
Change-Id: Id435e87664b2d2aa0ba69f2df1c1fad431651963

tests/v2/test_schemas.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from jsonpatch import JsonPatch
 import testtools
 import warlock
 
@@ -53,6 +54,11 @@ _SCHEMA = schemas.Schema({
 })
 
 
+def compare_json_patches(a, b):
+    """Return 0 if a and b describe the same JSON patch."""
+    return JsonPatch.from_string(a) == JsonPatch.from_string(b)
+
+
 class TestSchemaProperty(testtools.TestCase):
     def test_property_minimum(self):
         prop = schemas.SchemaProperty('size')
@@ -111,7 +117,7 @@ class TestSchemaBasedModel(testtools.TestCase):
 
         patch = original.patch
         expected = '[{"path": "/color", "value": "red", "op": "replace"}]'
-        self.assertEqual(patch, expected)
+        self.assertTrue(compare_json_patches(patch, expected))
 
     def test_patch_should_add_extra_properties(self):
         obj = {
@@ -123,7 +129,7 @@ class TestSchemaBasedModel(testtools.TestCase):
 
         patch = original.patch
         expected = '[{"path": "/weight", "value": "10", "op": "add"}]'
-        self.assertEqual(patch, expected)
+        self.assertTrue(compare_json_patches(patch, expected))
 
     def test_patch_should_replace_extra_properties(self):
         obj = {
@@ -136,7 +142,7 @@ class TestSchemaBasedModel(testtools.TestCase):
 
         patch = original.patch
         expected = '[{"path": "/weight", "value": "22", "op": "replace"}]'
-        self.assertEqual(patch, expected)
+        self.assertTrue(compare_json_patches(patch, expected))
 
     def test_patch_should_remove_extra_properties(self):
         obj = {
@@ -149,7 +155,7 @@ class TestSchemaBasedModel(testtools.TestCase):
 
         patch = original.patch
         expected = '[{"path": "/weight", "op": "remove"}]'
-        self.assertEqual(patch, expected)
+        self.assertTrue(compare_json_patches(patch, expected))
 
     def test_patch_should_remove_core_properties(self):
         obj = {
@@ -162,4 +168,4 @@ class TestSchemaBasedModel(testtools.TestCase):
 
         patch = original.patch
         expected = '[{"path": "/color", "op": "remove"}]'
-        self.assertEqual(patch, expected)
+        self.assertTrue(compare_json_patches(patch, expected))