replace assert statement with unittest.assertXXX

There are two concerns to do this:

* assert statement will not be executed when running under optimized
  mode (even though we don't really do this currently)
* unittest.assertXXX provides more detailed message when test fail,
  for example, assert count == 2 will only have AssertionError, but
  unittest.assertXXX can tell you the test fail because 1 != 2

This patch replaces assert statement with unittest.assertXXX in our
test code.

Note, not all assert statements are replaced because some of them are
not aiming at the test result.

Change-Id: Ida44bf6876e6fa60a4d8213f1cdad6edefb34cab
Closes-Bug: #1397883

heat/tests/api/openstack_v1/test_stacks.py

@@ -391,7 +391,7 @@ class StackControllerTest(tools.ControllerTest, common.HeatTestCase):
 
         result = self.controller.index(req, tenant_id=self.tenant)
         self.assertNotIn('count', result)
-        assert not engine.count_stacks.called
+        self.assertFalse(engine.count_stacks.called)
 
     def test_index_with_count_is_invalid(self, mock_enforce):
         self._mock_enforce_setup(mock_enforce, 'index', True)

heat/tests/db/test_sqlalchemy_api.py

@@ -144,14 +144,14 @@ class SqlAlchemyTest(common.HeatTestCase):
         query = mock.Mock()
         db_api._filter_and_page_query(self.ctx, query)
 
-        assert mock_paginate_query.called
+        self.assertTrue(mock_paginate_query.called)
 
     @mock.patch.object(db_api, '_events_paginate_query')
     def test_events_filter_and_page_query(self, mock_events_paginate_query):
         query = mock.Mock()
         db_api._events_filter_and_page_query(self.ctx, query)
 
-        assert mock_events_paginate_query.called
+        self.assertTrue(mock_events_paginate_query.called)
 
     @mock.patch.object(db_api.db_filters, 'exact_filter')
     def test_filter_and_page_query_handles_no_filters(self, mock_db_filter):
@@ -174,7 +174,7 @@ class SqlAlchemyTest(common.HeatTestCase):
         filters = {'foo': 'bar'}
         db_api._filter_and_page_query(self.ctx, query, filters=filters)
 
-        assert mock_db_filter.called
+        self.assertTrue(mock_db_filter.called)
 
     @mock.patch.object(db_api.db_filters, 'exact_filter')
     def test_events_filter_and_page_query_applies_filters(self,
@@ -183,7 +183,7 @@ class SqlAlchemyTest(common.HeatTestCase):
         filters = {'foo': 'bar'}
         db_api._events_filter_and_page_query(self.ctx, query, filters=filters)
 
-        assert mock_db_filter.called
+        self.assertTrue(mock_db_filter.called)
 
     @mock.patch.object(db_api, '_paginate_query')
     def test_filter_and_page_query_whitelists_sort_keys(self,

heat/tests/test_stack_lock.py

@@ -168,7 +168,7 @@ class StackLockTest(common.HeatTestCase):
                                  stack_lock_object.StackLock.create.call_count)
                 raise exception.ActionInProgress
         self.assertRaises(exception.ActionInProgress, check_thread_lock)
-        assert not stack_lock_object.StackLock.release.called
+        self.assertFalse(stack_lock_object.StackLock.release.called)
 
     def test_thread_lock_context_mgr_no_exception(self):
         stack_lock_object.StackLock.create = mock.Mock(return_value=None)
@@ -177,7 +177,7 @@ class StackLockTest(common.HeatTestCase):
                                      self.engine_id)
         with slock.thread_lock():
             self.assertEqual(1, stack_lock_object.StackLock.create.call_count)
-        assert not stack_lock_object.StackLock.release.called
+        self.assertFalse(stack_lock_object.StackLock.release.called)
 
     def test_try_thread_lock_context_mgr_exception(self):
         stack_lock_object.StackLock.create = mock.Mock(return_value=None)
@@ -200,7 +200,7 @@ class StackLockTest(common.HeatTestCase):
                                      self.engine_id)
         with slock.try_thread_lock():
             self.assertEqual(1, stack_lock_object.StackLock.create.call_count)
-        assert not stack_lock_object.StackLock.release.called
+        self.assertFalse(stack_lock_object.StackLock.release.called)
 
     def test_try_thread_lock_context_mgr_existing_lock(self):
         stack_lock_object.StackLock.create = mock.Mock(return_value=1234)
@@ -214,4 +214,4 @@ class StackLockTest(common.HeatTestCase):
                                  stack_lock_object.StackLock.create.call_count)
                 raise self.TestThreadLockException
         self.assertRaises(self.TestThreadLockException, check_thread_lock)
-        assert not stack_lock_object.StackLock.release.called
+        self.assertFalse(stack_lock_object.StackLock.release.called)