Add test to verify bad query behavior of xblock_handler

cms/djangoapps/contentstore/tests/test_import.py

@@ -157,15 +157,15 @@ class ContentStoreImportTest(ModuleStoreTestCase):
         store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
 
         # we try to refresh the inheritance tree for each update_item in the import
-        with check_exact_number_of_calls(store, store.refresh_cached_metadata_inheritance_tree, 28):
+        with check_exact_number_of_calls(store, "refresh_cached_metadata_inheritance_tree", 28):
 
             # _get_cached_metadata_inheritance_tree should be called only once
-            with check_exact_number_of_calls(store, store._get_cached_metadata_inheritance_tree, 1):
+            with check_exact_number_of_calls(store, "_get_cached_metadata_inheritance_tree", 1):
 
                 # with bulk-edit in progress, the inheritance tree should be recomputed only at the end of the import
                 # NOTE: On Jenkins, with memcache enabled, the number of calls here is only 1.
                 #       Locally, without memcache, the number of calls is actually 2 (once more during the publish step)
-                with check_number_of_calls(store, store._compute_metadata_inheritance_tree, 2):
+                with check_number_of_calls(store, "_compute_metadata_inheritance_tree", 2):
                     self.load_test_import_course()
 
     def test_rewrite_reference_list(self):

cms/djangoapps/contentstore/tests/utils.py

@@ -98,17 +98,23 @@ class CourseTestCase(ModuleStoreTestCase):
             nonstaff.is_authenticated = True
         return client, nonstaff
 
-    def populate_course(self):
+    def populate_course(self, branching=2):
         """
-        Add 2 chapters, 4 sections, 8 verticals, 16 problems to self.course (branching 2)
+        Add k chapters, k^2 sections, k^3 verticals, k^4 problems to self.course (where k = branching)
         """
         user_id = self.user.id
+        self.populated_usage_keys = {}
+
         def descend(parent, stack):
-            xblock_type = stack.pop(0)
-            for _ in range(2):
+            if not stack:
+                return
+
+            xblock_type = stack[0]
+            for _ in range(branching):
                 child = ItemFactory.create(category=xblock_type, parent_location=parent.location, user_id=user_id)
-                if stack:
-                    descend(child, stack)
+                print child.location
+                self.populated_usage_keys.setdefault(xblock_type, []).append(child.location)
+                descend(child, stack[1:])
 
         descend(self.course, ['chapter', 'sequential', 'vertical', 'problem'])
 

cms/djangoapps/contentstore/views/item.py

@@ -756,7 +756,7 @@ def _compute_visibility_state(xblock, child_info, is_unit_with_changes):
         return VisibilityState.needs_attention
     is_unscheduled = xblock.start == DEFAULT_START_DATE
     is_live = datetime.now(UTC) > xblock.start
-    children = child_info and child_info['children']
+    children = child_info and child_info.get('children', [])
     if children and len(children) > 0:
         all_staff_only = True
         all_unscheduled = True

cms/djangoapps/contentstore/views/tests/test_item.py

@@ -26,7 +26,7 @@ from student.tests.factories import UserFactory
 from xmodule.capa_module import CapaDescriptor
 from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore.tests.factories import ItemFactory
+from xmodule.modulestore.tests.factories import ItemFactory, check_mongo_calls
 from xmodule.x_module import STUDIO_VIEW, STUDENT_VIEW
 from xblock.exceptions import NoSuchHandlerError
 from opaque_keys.edx.keys import UsageKey, CourseKey
@@ -83,7 +83,8 @@ class ItemTest(CourseTestCase):
         return self.response_usage_key(resp)
 
 
-class GetItem(ItemTest):
+@ddt.ddt
+class GetItemTest(ItemTest):
     """Tests for '/xblock' GET url."""
 
     def _get_container_preview(self, usage_key):
@@ -100,6 +101,25 @@ class GetItem(ItemTest):
         self.assertIsNotNone(resources)
         return html, resources
 
+    @ddt.data(
+        (1, 21, 23, 35, 37),
+        (2, 22, 24, 38, 39),
+        (3, 23, 25, 41, 41),
+    )
+    @ddt.unpack
+    def test_get_query_count(self, branching_factor, chapter_queries, section_queries, unit_queries, problem_queries):
+        self.populate_course(branching_factor)
+        # Retrieve it
+        with check_mongo_calls(chapter_queries):
+            self.client.get(reverse_usage_url('xblock_handler', self.populated_usage_keys['chapter'][-1]))
+        with check_mongo_calls(section_queries):
+            self.client.get(reverse_usage_url('xblock_handler', self.populated_usage_keys['sequential'][-1]))
+        with check_mongo_calls(unit_queries):
+            self.client.get(reverse_usage_url('xblock_handler', self.populated_usage_keys['vertical'][-1]))
+        with check_mongo_calls(problem_queries):
+            self.client.get(reverse_usage_url('xblock_handler', self.populated_usage_keys['problem'][-1]))
+
+
     def test_get_vertical(self):
         # Add a vertical
         resp = self.create_xblock(category='vertical')

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

@@ -10,6 +10,7 @@ from xmodule.modulestore.django import modulestore, clear_existing_modulestores
 from xmodule.modulestore import ModuleStoreEnum
 import datetime
 import pytz
+from request_cache.middleware import RequestCache
 from xmodule.tabs import CoursewareTab, CourseInfoTab, StaticTab, DiscussionTab, ProgressTab, WikiTab
 from xmodule.modulestore.tests.sample_courses import default_block_info_tree, TOY_BLOCK_INFO_TREE
 from xmodule.modulestore.tests.mongo_connection import MONGO_PORT_NUM, MONGO_HOST
@@ -275,6 +276,8 @@ class ModuleStoreTestCase(TestCase):
         # the next time they are accessed.
         # We do this at *both* setup and teardown just to be safe.
         clear_existing_modulestores()
+        # clear RequestCache to emulate its clearance after each http request.
+        RequestCache().clear_request_cache()
 
         # Call superclass implementation
         super(ModuleStoreTestCase, self)._post_teardown()

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

@@ -217,12 +217,12 @@ class ItemFactory(XModuleFactory):
 
 
 @contextmanager
-def check_exact_number_of_calls(object_with_method, method, num_calls, method_name=None):
+def check_exact_number_of_calls(object_with_method, method_name, num_calls):
     """
     Instruments the given method on the given object to verify the number of calls to the
     method is exactly equal to 'num_calls'.
     """
-    with check_number_of_calls(object_with_method, method, num_calls, num_calls, method_name):
+    with check_number_of_calls(object_with_method, method_name, num_calls, num_calls):
         yield