def test_simple_dependency(self, *args, **kwargs):
"""
Tests creating a DAG of task dependencies when there is only one event
"""
A = self.create_task_class(('a',), (), ('a',))
B = self.create_task_class((), ('a',), ())
# Is the event dependency built correctly
events = BaseTask.build_task_event_dependency_graph()
self.assertEqual(len(events), 1)
self.assertEqual(len(events['a'][0]), 1)
self.assertIn(A, events['a'][0])
self.assertEqual(len(events['a'][1]), 1)
self.assertIn(B, events['a'][1])
# Is the DAG built correctly
g = BaseTask.build_full_task_dag()
self.assertEqual(len(g.all_nodes), 2)
self.assertIn(A, g.all_nodes)
self.assertIn(B, g.all_nodes)
# B depends on A
self.assertIn(B, g.dependent_nodes(A))
