Added test to exercise library root paged rendering

common/lib/xmodule/xmodule/modulestore/tests/test_libraries.py

@@ -207,6 +207,44 @@ class TestLibraries(MixedSplitTestCase):
                 result = library.render(AUTHOR_VIEW, context)
         self.assertIn(message, result.content)
 
+    @patch('xmodule.modulestore.split_mongo.caching_descriptor_system.CachingDescriptorSystem.render', VanillaRuntime.render)
+    def test_library_author_view_with_paging(self):
+        """
+        Test that LibraryRoot.author_view can apply paging
+        We have to patch the runtime (module system) in order to be able to
+        render blocks in our test environment.
+        """
+        library = LibraryFactory.create(modulestore=self.store)
+        # Add five HTML blocks to the library:
+        blocks = [
+            ItemFactory.create(
+                category="html",
+                parent_location=library.location,
+                user_id=self.user_id,
+                publish_item=False,
+                modulestore=self.store,
+                data="HtmlBlock"+str(i)
+            )
+            for i in range(5)
+        ]
+        library = self.store.get_library(library.location.library_key)
+
+        def render_and_check_contents(page, page_size):
+            context = {'reorderable_items': set(), 'paging': {'page_number': page, 'page_size': page_size}}
+            expected_blocks = blocks[page_size*page:page_size*(page+1)]
+            result = library.render(AUTHOR_VIEW, context)
+
+            for expected_block in expected_blocks:
+                self.assertIn(expected_block.data, result.content)
+
+        hello_render = lambda block, _: Fragment(block.data)
+        with patch('xmodule.html_module.HtmlDescriptor.author_view', hello_render, create=True):
+            with patch('xmodule.x_module.DescriptorSystem.applicable_aside_types', lambda self, block: []):
+                render_and_check_contents(0, 3)
+                render_and_check_contents(1, 3)
+                render_and_check_contents(0, 2)
+                render_and_check_contents(1, 2)
+
     def test_xblock_in_lib_have_published_version_returns_false(self):
         library = LibraryFactory.create(modulestore=self.store)
         block = ItemFactory.create(