Switch from unittest2 compat methods to Python 3.x methods

With the removal of Python 2.x we can remove the unittest2 compat
wrappers and switch to assertCountEqual instead of assertItemsEqual.

Change-Id: I682997a4fceb139419a4b12d9c8fc6c504c329d5

HACKING.rst

@@ -16,3 +16,4 @@ Below you can find a list of checks specific to this repository.
 - [N344] Python 3: Do not use filter(lambda obj: test(obj), data). Replace it
          with [obj for obj in data if test(obj)].
 - [N347] Test code must not import mock library
+- [N348] Detect usage of assertItemsEqual

ovn_octavia_provider/hacking/checks.py

@@ -181,3 +181,15 @@ def check_no_import_mock(logical_line, filename, noqa):
     for regex in import_mock, import_from_mock:
         if re.match(regex, logical_line):
             yield(0, msg)
+
+
+@core.flake8ext
+def check_assertcountequal(logical_line, filename):
+    """N348 - Enforce using assertCountEqual."""
+
+    msg = ("N348: Use assertCountEqual(expected, observed) "
+           "instead of assertItemsEqual(observed, expected)")
+
+    if 'ovn_octavia_provider/tests/' in filename:
+        if re.search(r"assertItemsEqual\([^,]*,\s*(,[^,]*)?", logical_line):
+            yield (0, msg)

ovn_octavia_provider/tests/functional/base.py

@@ -192,11 +192,10 @@ class TestOvnOctaviaBase(base.TestOVNFunctionalBase,
 
     def _validate_loadbalancers(self, expected_lbs):
         observed_lbs = self._get_loadbalancers()
-        # NOTE (mjozefcz): assertItemsEqual works only on first level
+        # NOTE (mjozefcz): assertCountEqual works only on first level
-        # of comparison, if dicts inside dics are in diffrent
+        # of comparison, if dicts inside dicts are in different
         # order it would fail.
-        self.assertEqual(len(expected_lbs),
+        self.assertEqual(len(expected_lbs), len(observed_lbs))
-                         len(observed_lbs))
         for expected_lb in expected_lbs:
             # search for LB with same name and protocol
             found = False
@@ -308,7 +307,7 @@ class TestOvnOctaviaBase(base.TestOVNFunctionalBase,
                         calls_found.append(expected_status)
                         break
             # Validate if we found all expected calls.
-            self.assertItemsEqual(expected_statuses, calls_found)
+            self.assertCountEqual(expected_statuses, calls_found)
 
     def _wait_for_status_and_validate(self, lb_data, expected_status,
                                       check_call=True):

tox.ini

@@ -118,6 +118,7 @@ extension =
   N343 = checks:check_no_imports_from_tests
   N344 = checks:check_python3_no_filter
   N347 = checks:check_no_import_mock
+  N348 = checks:check_assertcountequal
 paths =./ovn_octavia_provider/hacking
 
 [testenv:genconfig]