Fixes unit tests throwing errors, related to Horizon function.

Currently, 11 unit tests are failing because Horizon
changed some of its behavior related to how pagesizes are
calculated from request objects.

This is the commit in Horizon that appears to have caused things
to break in these unit tests:
https://review.openstack.org/#/c/155939/13/horizon/utils/functions.py

This fix mocks out the function in Horizon that does the pagesize
calculation.

Change-Id: I983e83033b8eab25f79f505d2e57ef1e6b86873b
Closes-Bug: #1650029

muranodashboard/tests/unit/categories/test_views.py

@@ -29,7 +29,6 @@ class TestCategoriesView(testtools.TestCase):
         self.categories_view._more = False
 
         mock_request = mock.Mock()
-        mock_request.session = {'horizon_pagesize': 2}
         self.categories_view.request = mock_request
 
         self.assertEqual(tables.CategoriesTable,
@@ -39,6 +38,10 @@ class TestCategoriesView(testtools.TestCase):
         self.assertEqual('Application Categories',
                          self.categories_view.page_title)
 
+        mock_horizon_utils = mock.patch.object(views, 'utils').start()
+        mock_horizon_utils.get_page_size.return_value = 2
+        self.addCleanup(mock.patch.stopall)
+
     def test_has_prev_data(self):
         self.assertFalse(self.categories_view.has_prev_data(None))
 

muranodashboard/tests/unit/environments/test_views.py

@@ -168,7 +168,6 @@ class TestDetailServiceView(testtools.TestCase):
             'environment_id': 'foo_env_id'
         }
         self.mock_request = mock.Mock(GET={})
-        self.mock_request.session = {'horizon_pagesize': 123}
         self.mock_request.user.service_catalog = None
         self.mock_request.is_ajax.return_value = True
         self.mock_request.horizon = {

muranodashboard/tests/unit/images/test_views.py

@@ -28,7 +28,6 @@ class TestMarkedImagesView(testtools.TestCase):
         super(TestMarkedImagesView, self).setUp()
 
         mock_request = mock.Mock(horizon={'async_messages': []})
-        mock_request.session = {'horizon_pagesize': 2}
         self.images_view = views.MarkedImagesView(request=mock_request)
         self.images_view._prev = False
         self.images_view._more = False
@@ -38,6 +37,10 @@ class TestMarkedImagesView(testtools.TestCase):
         self.assertEqual('images/index.html', self.images_view.template_name)
         self.assertEqual('Marked Images', self.images_view.page_title)
 
+        mock_horizon_utils = mock.patch.object(views, 'utils').start()
+        mock_horizon_utils.get_page_size.return_value = 2
+        self.addCleanup(mock.patch.stopall)
+
     def _get_mock_image(self, prefix):
         image_info = {}
         if prefix:

muranodashboard/tests/unit/packages/test_views.py

@@ -1126,7 +1126,7 @@ class TestPackageDefinitionsView(helpers.APITestCase):
         mock_token.__getitem__.return_value = 'foo_token_id'
         self.mock_request = mock.MagicMock(
             name='mock_request', GET={'sort_dir': 'asc'},
-            session={'horizon_pagesize': '123', 'token': mock_token})
+            session={'token': mock_token})
 
         self.pkg_definitions_view.request = self.mock_request
         self.original_get_filters = self.pkg_definitions_view.get_filters
@@ -1140,6 +1140,8 @@ class TestPackageDefinitionsView(helpers.APITestCase):
         self.assertFalse(self.pkg_definitions_view.has_more_data(None))
         self.assertFalse(self.pkg_definitions_view.has_prev_data(None))
 
+        mock_horizon_utils = mock.patch.object(views, 'utils').start()
+        mock_horizon_utils.get_page_size.return_value = 123
         self.addCleanup(mock.patch.stopall)
 
     @mock.patch.object(views, 'pkg_api')