def test_get_parents(self):
'''
get_parent_locations(locator, [usage_id], [branch]): [BlockUsageLocator]
'''
locator = CourseLocator(course_id="GreekHero", branch='draft')
parents = modulestore().get_parent_locations(locator, usage_id='chapter1')
self.assertEqual(len(parents), 1)
self.assertEqual(parents[0].usage_id, 'head12345')
self.assertEqual(parents[0].course_id, "GreekHero")
locator.usage_id = 'chapter2'
parents = modulestore().get_parent_locations(locator)
self.assertEqual(len(parents), 1)
self.assertEqual(parents[0].usage_id, 'head12345')
parents = modulestore().get_parent_locations(locator, usage_id='nosuchblock')
self.assertEqual(len(parents), 0)
