Merge "Add assertSetEqual to base test class"

keystone/tests/core.py

@@ -523,3 +523,56 @@ class TestCase(testtools.TestCase):
                 raise
         else:
             s.close()
+
+    def assertSetEqual(self, set1, set2, msg=None):
+        # TODO(morganfainberg): Remove this and self._assertSetEqual once
+        # support for python 2.6 is no longer needed.
+        if (sys.version_info < (2, 7)):
+            return self._assertSetEqual(set1, set2, msg=None)
+        else:
+            # use the native assertSetEqual
+            return super(TestCase, self).assertSetEqual(set1, set2, msg=msg)
+
+    def _assertSetEqual(self, set1, set2, msg=None):
+        """A set-specific equality assertion.
+
+        Args:
+            set1: The first set to compare.
+            set2: The second set to compare.
+            msg: Optional message to use on failure instead of a list of
+                    differences.
+
+        assertSetEqual uses ducktyping to support different types of sets, and
+        is optimized for sets specifically (parameters must support a
+        difference method).
+        """
+        try:
+            difference1 = set1.difference(set2)
+        except TypeError as e:
+            self.fail('invalid type when attempting set difference: %s' % e)
+        except AttributeError as e:
+            self.fail('first argument does not support set difference: %s' % e)
+
+        try:
+            difference2 = set2.difference(set1)
+        except TypeError as e:
+            self.fail('invalid type when attempting set difference: %s' % e)
+        except AttributeError as e:
+            self.fail('second argument does not support set difference: %s' %
+                      e)
+
+        if not (difference1 or difference2):
+            return
+
+        lines = []
+        if difference1:
+            lines.append('Items in the first set but not the second:')
+            for item in difference1:
+                lines.append(repr(item))
+        if difference2:
+            lines.append('Items in the second set but not the first:')
+            for item in difference2:
+                lines.append(repr(item))
+
+        standardMsg = '\n'.join(lines)
+        self.fail(self._formatMessage(msg, standardMsg))