Add fixtures for mocking Course Structure API
Add fixtures for mocking Course Structure API

edx/edx-analytics-dashboard,edx/edx-analytics-dashboard,Stanford-Online/edx-analytics-dashboard,edx/edx-analytics-dashboard,Stanford-Online/edx-analytics-dashboard,Stanford-Online/edx-analytics-dashboard,edx/edx-analytics-dashboard,Stanford-Online/edx-analytics-dashboard