Python Vertex.has_predecessor примеры использования

Пример #1

def test_has_and_set_predecessor():
    end_v = Vertex('2')
    assert end_v.has_predecessor() is False

    start_v = Vertex('1')  # The predecessor
    end_v.set_predecessor(start_v)
    assert end_v.has_predecessor()

Пример #2

def test_has_predecessor__DNE_returns_False():
    end_v = Vertex('2')
    assert end_v.has_predecessor() is False