Python DAG.add_dependency Examples

Example #1

def test__DAG_get_upstream():
    A, B = get_two_tasks()
    dag = DAG()
    dag.add_dependency(B, depends_on=A)
    assert dag.get_upstream() is not None
    assert dag.get_upstream()[B] == {A,}
    assert dag.get_upstream() == {B: {A,}}, 'Task A is not upstream'

Example #2

def test__DAG_get_downstream():
    A, B = get_two_tasks()
    dag = DAG()
    dag.add_dependency(B, depends_on=A)
    assert dag.get_downstream() is not None
    assert dag.get_downstream()[A] == {B,}
    assert dag.get_downstream() == {A: {B,}}, 'Task B is not downstream'

Example #3

def test__DAG_is_cyclic():
    A, B = get_two_tasks()
    dag = DAG()

    dag.add_dependency(B, depends_on=A)
    assert not dag.is_cyclic(), 'acyclic graph idenfied as cyclic'
    
    with pytest.raises(CyclicGraphError):
        dag.add_dependency(A, depends_on=B)

Example #4

def test__DAG_add_dependency_detect_cycle():
    A, B = get_two_tasks()
    dag = DAG()
    dag.add_dependency(B, A)
    with pytest.raises(CyclicGraphError):
        dag.add_dependency(A, B)

Example #5

def test__DAG_add_dependency():
    A, B = get_two_tasks()
    dag = DAG()
    dag.add_dependency(B, A)
    assert dag._edges[A] == set([B])

Example #6

def test__DAG_get_sinks():
    A, B = get_two_tasks()
    dag = DAG()
    dag.add_dependency(B, depends_on=A)
    assert dag.get_sinks() is not None
    assert dag.get_sinks() == {B,}