Add query count tests to DjangoKeyValueStore/FieldDataCache

lms/djangoapps/courseware/tests/test_model_data.py

@@ -106,48 +106,68 @@ class TestStudentModuleStorage(OtherUserFailureTestMixin, TestCase):
         student_module = StudentModuleFactory(state=json.dumps({'a_field': 'a_value', 'b_field': 'b_value'}))
         self.user = student_module.student
         self.assertEqual(self.user.id, 1)   # check our assumption hard-coded in the key functions above.
-        self.field_data_cache = FieldDataCache([mock_descriptor([mock_field(Scope.user_state, 'a_field')])], course_id, self.user)
+
+        # There should be only one query to load a single descriptor with a single user_state field
+        with self.assertNumQueries(1):
+            self.field_data_cache = FieldDataCache([mock_descriptor([mock_field(Scope.user_state, 'a_field')])], course_id, self.user)
+
         self.kvs = DjangoKeyValueStore(self.field_data_cache)
 
     def test_get_existing_field(self):
         "Test that getting an existing field in an existing StudentModule works"
-        self.assertEquals('a_value', self.kvs.get(user_state_key('a_field')))
+        # This should only read from the cache, not the database
+        with self.assertNumQueries(0):
+            self.assertEquals('a_value', self.kvs.get(user_state_key('a_field')))
 
     def test_get_missing_field(self):
         "Test that getting a missing field from an existing StudentModule raises a KeyError"
-        self.assertRaises(KeyError, self.kvs.get, user_state_key('not_a_field'))
+        # This should only read from the cache, not the database
+        with self.assertNumQueries(0):
+            self.assertRaises(KeyError, self.kvs.get, user_state_key('not_a_field'))
 
     def test_set_existing_field(self):
         "Test that setting an existing user_state field changes the value"
-        self.kvs.set(user_state_key('a_field'), 'new_value')
+        # We are updating a problem, so we write to courseware_studentmodulehistory
+        # as well as courseware_studentmodule
+        with self.assertNumQueries(3):
+            self.kvs.set(user_state_key('a_field'), 'new_value')
         self.assertEquals(1, StudentModule.objects.all().count())
         self.assertEquals({'b_field': 'b_value', 'a_field': 'new_value'}, json.loads(StudentModule.objects.all()[0].state))
 
     def test_set_missing_field(self):
         "Test that setting a new user_state field changes the value"
-        self.kvs.set(user_state_key('not_a_field'), 'new_value')
+        # We are updating a problem, so we write to courseware_studentmodulehistory
+        # as well as courseware_studentmodule
+        with self.assertNumQueries(3):
+            self.kvs.set(user_state_key('not_a_field'), 'new_value')
         self.assertEquals(1, StudentModule.objects.all().count())
         self.assertEquals({'b_field': 'b_value', 'a_field': 'a_value', 'not_a_field': 'new_value'}, json.loads(StudentModule.objects.all()[0].state))
 
     def test_delete_existing_field(self):
         "Test that deleting an existing field removes it from the StudentModule"
-        self.kvs.delete(user_state_key('a_field'))
+        # We are updating a problem, so we write to courseware_studentmodulehistory
+        # as well as courseware_studentmodule
+        with self.assertNumQueries(3):
+            self.kvs.delete(user_state_key('a_field'))
         self.assertEquals(1, StudentModule.objects.all().count())
         self.assertRaises(KeyError, self.kvs.get, user_state_key('not_a_field'))
 
     def test_delete_missing_field(self):
         "Test that deleting a missing field from an existing StudentModule raises a KeyError"
-        self.assertRaises(KeyError, self.kvs.delete, user_state_key('not_a_field'))
+        with self.assertNumQueries(0):
+            self.assertRaises(KeyError, self.kvs.delete, user_state_key('not_a_field'))
         self.assertEquals(1, StudentModule.objects.all().count())
         self.assertEquals({'b_field': 'b_value', 'a_field': 'a_value'}, json.loads(StudentModule.objects.all()[0].state))
 
     def test_has_existing_field(self):
         "Test that `has` returns True for existing fields in StudentModules"
-        self.assertTrue(self.kvs.has(user_state_key('a_field')))
+        with self.assertNumQueries(0):
+            self.assertTrue(self.kvs.has(user_state_key('a_field')))
 
     def test_has_missing_field(self):
         "Test that `has` returns False for missing fields in StudentModule"
-        self.assertFalse(self.kvs.has(user_state_key('not_a_field')))
+        with self.assertNumQueries(0):
+            self.assertFalse(self.kvs.has(user_state_key('not_a_field')))
 
     def construct_kv_dict(self):
         """Construct a kv_dict that can be passed to set_many"""
@@ -160,7 +180,12 @@ class TestStudentModuleStorage(OtherUserFailureTestMixin, TestCase):
     def test_set_many(self):
         "Test setting many fields that are scoped to Scope.user_state"
         kv_dict = self.construct_kv_dict()
-        self.kvs.set_many(kv_dict)
+
+        # Scope.user_state is stored in a single row in the database, so we only
+        # need to send a single update to that table.
+        # We also are updating a problem, so we write to courseware student module history
+        with self.assertNumQueries(3):
+            self.kvs.set_many(kv_dict)
 
         for key in kv_dict:
             self.assertEquals(self.kvs.get(key), kv_dict[key])
@@ -185,19 +210,26 @@ class TestMissingStudentModule(TestCase):
 
         self.user = UserFactory.create(username='user')
         self.assertEqual(self.user.id, 1)   # check our assumption hard-coded in the key functions above.
-        self.field_data_cache = FieldDataCache([mock_descriptor()], course_id, self.user)
+
+        # The descriptor has no fields, so FDC shouldn't send any queries
+        with self.assertNumQueries(0):
+            self.field_data_cache = FieldDataCache([mock_descriptor()], course_id, self.user)
         self.kvs = DjangoKeyValueStore(self.field_data_cache)
 
     def test_get_field_from_missing_student_module(self):
         "Test that getting a field from a missing StudentModule raises a KeyError"
-        self.assertRaises(KeyError, self.kvs.get, user_state_key('a_field'))
+        with self.assertNumQueries(0):
+            self.assertRaises(KeyError, self.kvs.get, user_state_key('a_field'))
 
     def test_set_field_in_missing_student_module(self):
         "Test that setting a field in a missing StudentModule creates the student module"
         self.assertEquals(0, len(self.field_data_cache.cache))
         self.assertEquals(0, StudentModule.objects.all().count())
 
-        self.kvs.set(user_state_key('a_field'), 'a_value')
+        # We are updating a problem, so we write to courseware_studentmodulehistory
+        # as well as courseware_studentmodule
+        with self.assertNumQueries(6):
+            self.kvs.set(user_state_key('a_field'), 'a_value')
 
         self.assertEquals(1, len(self.field_data_cache.cache))
         self.assertEquals(1, StudentModule.objects.all().count())
@@ -210,11 +242,13 @@ class TestMissingStudentModule(TestCase):
 
     def test_delete_field_from_missing_student_module(self):
         "Test that deleting a field from a missing StudentModule raises a KeyError"
-        self.assertRaises(KeyError, self.kvs.delete, user_state_key('a_field'))
+        with self.assertNumQueries(0):
+            self.assertRaises(KeyError, self.kvs.delete, user_state_key('a_field'))
 
     def test_has_field_for_missing_student_module(self):
         "Test that `has` returns False for missing StudentModules"
-        self.assertFalse(self.kvs.has(user_state_key('a_field')))
+        with self.assertNumQueries(0):
+            self.assertFalse(self.kvs.has(user_state_key('a_field')))
 
 
 class StorageTestBase(object):
@@ -240,51 +274,64 @@ class StorageTestBase(object):
         self.mock_descriptor = mock_descriptor([
             mock_field(self.scope, 'existing_field'),
             mock_field(self.scope, 'other_existing_field')])
-        self.field_data_cache = FieldDataCache([self.mock_descriptor], course_id, self.user)
+        # Each field is stored as a separate row in the table,
+        # but we can query them in a single query
+        with self.assertNumQueries(1):
+            self.field_data_cache = FieldDataCache([self.mock_descriptor], course_id, self.user)
         self.kvs = DjangoKeyValueStore(self.field_data_cache)
 
     def test_set_and_get_existing_field(self):
-        self.kvs.set(self.key_factory('existing_field'), 'test_value')
-        self.assertEquals('test_value', self.kvs.get(self.key_factory('existing_field')))
+        with self.assertNumQueries(2):
+            self.kvs.set(self.key_factory('existing_field'), 'test_value')
+        with self.assertNumQueries(0):
+            self.assertEquals('test_value', self.kvs.get(self.key_factory('existing_field')))
 
     def test_get_existing_field(self):
         "Test that getting an existing field in an existing Storage Field works"
-        self.assertEquals('old_value', self.kvs.get(self.key_factory('existing_field')))
+        with self.assertNumQueries(0):
+            self.assertEquals('old_value', self.kvs.get(self.key_factory('existing_field')))
 
     def test_get_missing_field(self):
         "Test that getting a missing field from an existing Storage Field raises a KeyError"
-        self.assertRaises(KeyError, self.kvs.get, self.key_factory('missing_field'))
+        with self.assertNumQueries(0):
+            self.assertRaises(KeyError, self.kvs.get, self.key_factory('missing_field'))
 
     def test_set_existing_field(self):
         "Test that setting an existing field changes the value"
-        self.kvs.set(self.key_factory('existing_field'), 'new_value')
+        with self.assertNumQueries(2):
+            self.kvs.set(self.key_factory('existing_field'), 'new_value')
         self.assertEquals(1, self.storage_class.objects.all().count())
         self.assertEquals('new_value', json.loads(self.storage_class.objects.all()[0].value))
 
     def test_set_missing_field(self):
         "Test that setting a new field changes the value"
-        self.kvs.set(self.key_factory('missing_field'), 'new_value')
+        with self.assertNumQueries(4):
+            self.kvs.set(self.key_factory('missing_field'), 'new_value')
         self.assertEquals(2, self.storage_class.objects.all().count())
         self.assertEquals('old_value', json.loads(self.storage_class.objects.get(field_name='existing_field').value))
         self.assertEquals('new_value', json.loads(self.storage_class.objects.get(field_name='missing_field').value))
 
     def test_delete_existing_field(self):
         "Test that deleting an existing field removes it"
-        self.kvs.delete(self.key_factory('existing_field'))
+        with self.assertNumQueries(1):
+            self.kvs.delete(self.key_factory('existing_field'))
         self.assertEquals(0, self.storage_class.objects.all().count())
 
     def test_delete_missing_field(self):
         "Test that deleting a missing field from an existing Storage Field raises a KeyError"
-        self.assertRaises(KeyError, self.kvs.delete, self.key_factory('missing_field'))
+        with self.assertNumQueries(0):
+            self.assertRaises(KeyError, self.kvs.delete, self.key_factory('missing_field'))
         self.assertEquals(1, self.storage_class.objects.all().count())
 
     def test_has_existing_field(self):
         "Test that `has` returns True for an existing Storage Field"
-        self.assertTrue(self.kvs.has(self.key_factory('existing_field')))
+        with self.assertNumQueries(0):
+            self.assertTrue(self.kvs.has(self.key_factory('existing_field')))
 
     def test_has_missing_field(self):
         "Test that `has` return False for an existing Storage Field"
-        self.assertFalse(self.kvs.has(self.key_factory('missing_field')))
+        with self.assertNumQueries(0):
+            self.assertFalse(self.kvs.has(self.key_factory('missing_field')))
 
     def construct_kv_dict(self):
         """Construct a kv_dict that can be passed to set_many"""
@@ -298,15 +345,19 @@ class StorageTestBase(object):
         """Test that setting many regular fields at the same time works"""
         kv_dict = self.construct_kv_dict()
 
-        self.kvs.set_many(kv_dict)
+        # Each field is a separate row in the database, hence
+        # a separate query
+        with self.assertNumQueries(len(kv_dict)*3):
+            self.kvs.set_many(kv_dict)
         for key in kv_dict:
             self.assertEquals(self.kvs.get(key), kv_dict[key])
 
     def test_set_many_failure(self):
         """Test that setting many regular fields with a DB error """
         kv_dict = self.construct_kv_dict()
-        for key in kv_dict:
-            self.kvs.set(key, 'test value')
+        with self.assertNumQueries(6):
+            for key in kv_dict:
+                self.kvs.set(key, 'test value')
 
         with patch('django.db.models.Model.save', side_effect=[None, DatabaseError]):
             with self.assertRaises(KeyValueMultiSaveError) as exception_context: