def test_detect_cycle():
f = Flow(name="test")
t1 = Task()
t2 = Task()
f.add_edge(t1, t2)
with pytest.raises(ValueError):
f.add_edge(t2, t1, validate=True)
def test_add_edge_raise_error_for_downstream_parameter():
f = Flow(name="test")
t = Task()
p = Parameter("p")
with pytest.raises(ValueError) as exc:
f.add_edge(upstream_task=t, downstream_task=p)
assert "can not have upstream dependencies" in str(exc.value)
def test_validate_cycles():
f = Flow(name="test")
t1 = Task()
t2 = Task()
f.add_edge(t1, t2)
f.add_edge(t2, t1)
with pytest.raises(ValueError) as exc:
f.validate()
assert "cycle found" in str(exc.value).lower()
def test_validate_missing_edge_upstream_tasks():
f = Flow(name="test")
t1 = Task()
t2 = Task()
f.add_edge(t1, t2)
f.tasks.remove(t1)
with pytest.raises(ValueError) as exc:
f.validate()
assert "edges refer to tasks" in str(exc.value).lower()
def test_add_edge_raise_error_for_duplicate_key_if_validate():
f = Flow(name="test")
t = Task()
a = AddTask()
f.add_edge(upstream_task=t, downstream_task=a, key="x")
with pytest.raises(ValueError) as exc:
f.add_edge(upstream_task=t, downstream_task=a, key="x", validate=True)
assert "already been assigned" in str(exc.value)
def test_add_edge():
f = Flow(name="test")
t1 = Task()
t2 = Task()
f.add_edge(upstream_task=t1, downstream_task=t2)
assert f.upstream_tasks(t2) == set([t1])
assert f.upstream_tasks(t1) == set()
assert f.downstream_tasks(t2) == set()
assert f.downstream_tasks(t1) == set([t2])
assert f.edges_to(t2) == f.edges_from(t1)
def test_serialize_validates_invalid_flows(self):
t1, t2 = Task(), Task()
f = Flow(name="test")
f.add_edge(t1, t2)
# default settings should allow this even though it's illegal
f.add_edge(t2, t1)
with pytest.raises(ValueError) as exc:
f.serialize()
assert "cycle found" in str(exc).lower()
def test_serialization(self):
p1, t2, t3, = Parameter("1"), Task("2"), Task("3")
f = Flow(name="test", tasks=[p1, t2, t3])
f.add_edge(p1, t2)
f.add_edge(p1, t3)
serialized = f.serialize()
assert isinstance(serialized, dict)
assert len(serialized["tasks"]) == len(f.tasks)
def test_eager_cycle_detection_works():
with set_temporary_config({"flows.eager_edge_validation": True}):
f = Flow(name="test")
t1 = Task()
t2 = Task()
f.add_edge(t1, t2)
with pytest.raises(ValueError):
f.add_edge(t2, t1)
assert not prefect.config.flows.eager_edge_validation
def test_sorted_tasks():
"""
t1 -> t2 -> t3 -> t4
"""
f = Flow(name="test")
t1 = Task("1")
t2 = Task("2")
t3 = Task("3")
t4 = Task("4")
f.add_edge(t1, t2)
f.add_edge(t2, t3)
f.add_edge(t3, t4)
assert f.sorted_tasks() == (t1, t2, t3, t4)
def test_cache_all_downstream_edges(self):
f = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
f.add_edge(t1, t2)
f.all_downstream_edges()
key = ("all_downstream_edges", ())
f._cache[key] = 1
assert f.all_downstream_edges() == 1
f.add_edge(t2, t3)
assert f.all_downstream_edges() != 1
def test_eager_cycle_detection_defaults_false():
assert not prefect.config.flows.eager_edge_validation
f = Flow(name="test")
t1 = Task()
t2 = Task()
f.add_edge(t1, t2)
# no cycle detected
assert f.add_edge(t2, t1)
with pytest.raises(ValueError):
f.validate()
def test_sorted_tasks_with_invalid_start_task():
"""
t1 -> t2 -> t3 -> t4
t3 -> t5
"""
f = Flow(name="test")
t1 = Task("1")
t2 = Task("2")
t3 = Task("3")
f.add_edge(t1, t2)
with pytest.raises(ValueError) as exc:
f.sorted_tasks(root_tasks=[t3])
assert "not found in Flow" in str(exc.value)
def test_merge():
f1 = Flow(name="test")
f2 = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
f1.add_edge(t1, t2)
f2.add_edge(t2, t3)
f2.update(f1)
assert f2.tasks == set([t1, t2, t3])
assert len(f2.edges) == 2
def test_equality_based_on_edges(self):
f1 = Flow(name="test")
f2 = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
for f in [f1, f2]:
f.add_edge(t1, t2)
f.add_edge(t1, t3)
assert f1 == f2
f2.add_edge(t2, t3)
assert f1 != f2
def test_cache_survives_pickling(self):
f = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
f.add_edge(t1, t2)
f.sorted_tasks()
key = ("_sorted_tasks", (("root_tasks", ()), ))
f._cache[key] = 1
assert f.sorted_tasks() == 1
f2 = cloudpickle.loads(cloudpickle.dumps(f))
assert f2.sorted_tasks() == 1
f2.add_edge(t2, t3)
assert f2.sorted_tasks() != 1
def test_sorted_tasks_with_start_task():
"""
t1 -> t2 -> t3 -> t4
t3 -> t5
"""
f = Flow(name="test")
t1 = Task("1")
t2 = Task("2")
t3 = Task("3")
t4 = Task("4")
t5 = Task("5")
f.add_edge(t1, t2)
f.add_edge(t2, t3)
f.add_edge(t3, t4)
f.add_edge(t3, t5)
assert set(f.sorted_tasks(root_tasks=[])) == set([t1, t2, t3, t4, t5])
assert set(f.sorted_tasks(root_tasks=[t3])) == set([t3, t4, t5])
def test_cache_sorted_tasks(self):
f = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
f.add_edge(t1, t2)
f.sorted_tasks()
# check that cache holds result
key = ("_sorted_tasks", (("root_tasks", ()), ))
assert f._cache[key] == (t1, t2)
# check that cache is read
f._cache[key] = 1
assert f.sorted_tasks() == 1
f.add_edge(t2, t3)
assert f.sorted_tasks() == (t1, t2, t3)
def test_cache_terminal_tasks(self):
f = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
f.add_edge(t1, t2)
f.terminal_tasks()
# check that cache holds result
key = ("terminal_tasks", ())
assert f._cache[key] == set([t2])
# check that cache is read
f._cache[key] = 1
assert f.terminal_tasks() == 1
f.add_edge(t2, t3)
assert f.terminal_tasks() == set([t3])
def test_add_edge_returns_edge():
f = Flow(name="test")
t1 = Task()
t2 = Task()
edge = Edge(t1, t2)
added_edge = f.add_edge(upstream_task=t1, downstream_task=t2)
assert edge == added_edge
assert added_edge in f.edges
assert edge in f.edges
def test_cache_task_ids(self):
f = Flow(name="test")
t1 = Task()
t2 = Task()
t3 = Task()
f.add_edge(t1, t2)
ids = f.task_ids
# check that cache holds result
key = ("task_ids", ())
assert f._cache[key] == ids
# check that cache is read
f._cache[key] = 1
assert f.task_ids == 1
f.add_edge(t2, t3)
assert len(f.task_ids) == 3
def test_deserialization(self):
p1, t2, t3, = Parameter("1"), Task("2"), Task("3")
f = Flow(
name="hi",
tasks=[p1, t2, t3],
schedule=prefect.schedules.CronSchedule("0 0 * * *"),
)
f.add_edge(p1, t2)
f.add_edge(p1, t3)
serialized = f.serialize()
f2 = prefect.serialization.flow.FlowSchema().load(serialized)
assert len(f2.tasks) == 3
assert len(f2.edges) == 2
assert len(f2.reference_tasks()) == 2
assert {t.name for t in f2.reference_tasks()} == {"2", "3"}
assert f2.name == f.name
assert isinstance(f2.schedule, prefect.schedules.CronSchedule)
def test_sorted_tasks_with_ambiguous_sort():
"""
t1 -> bottleneck
t2 -> bottleneck
t3 -> bottleneck
bottleneck -> t4
bottleneck -> t5
bottleneck -> t6
"""
f = Flow(name="test")
t1 = Task("1")
t2 = Task("2")
t3 = Task("3")
t4 = Task("4")
t5 = Task("5")
t6 = Task("6")
bottleneck = Task("bottleneck")
f.add_edge(t1, bottleneck)
f.add_edge(t2, bottleneck)
f.add_edge(t3, bottleneck)
f.add_edge(bottleneck, t4)
f.add_edge(bottleneck, t5)
f.add_edge(bottleneck, t6)
tasks = f.sorted_tasks()
assert set(tasks[:3]) == set([t1, t2, t3])
assert list(tasks)[3] is bottleneck
assert set(tasks[4:]) == set([t4, t5, t6])
def test_skip_validate_edges():
f = Flow(name="test")
t1, t2 = Task(), Task() # these tasks don't support keyed edges
f.add_edge(t1, t2, key="x", validate=False)
f.add_edge(t2, t1, validate=False) # this introduces a cycle
def test_validate_edges():
with set_temporary_config({"flows.eager_edge_validation": True}):
f = Flow(name="test")
t1, t2 = Task(), Task() # these tasks don't support keyed edges
with pytest.raises(TypeError):
f.add_edge(t1, t2, key="x")
def test_validate_edges_kwarg():
f = Flow(name="test")
t1, t2 = Task(), Task() # these tasks don't support keyed edges
with pytest.raises(TypeError):
f.add_edge(t1, t2, key="x", validate=True)
def test_adding_edge_clears_cache(self):
f = Flow(name="test")
f._cache[1] = 2
f.add_edge(Task(), Task())
assert 1 not in f._cache