New lingo for tracking sequential tasks

Author: carver

tests/trinity/utils/test_ordered_task_preparation.py

@@ -0,0 +1,186 @@
+import asyncio
+from enum import Enum, auto
+
+from eth_utils import (
+    ValidationError,
+)
+from eth_utils.toolz import identity
+import pytest
+
+from trinity.utils.datastructures import (
+    OrderedTaskPreparation,
+)
+
+DEFAULT_TIMEOUT = 0.05
+
+
+async def wait(coro, timeout=DEFAULT_TIMEOUT):
+    return await asyncio.wait_for(coro, timeout=timeout)
+
+
+class OnePrereq(Enum):
+    one = auto()
+
+
+class TwoPrereqs(Enum):
+    Prereq1 = auto()
+    Prereq2 = auto()
+
+
+@pytest.mark.asyncio
+async def test_simplest_path():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    ti.set_finished_dependency(3)
+    ti.register_tasks((4, ))
+    ti.finish_prereq(TwoPrereqs.Prereq1, (4, ))
+    ti.finish_prereq(TwoPrereqs.Prereq2, (4, ))
+    ready = await wait(ti.ready_tasks())
+    assert ready == (4, )
+
+
+@pytest.mark.asyncio
+async def test_cannot_finish_before_prepare():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    ti.set_finished_dependency(3)
+    with pytest.raises(ValidationError):
+        ti.finish_prereq(TwoPrereqs.Prereq1, (4, ))
+
+
+@pytest.mark.asyncio
+async def test_two_steps_simultaneous_complete():
+    ti = OrderedTaskPreparation(OnePrereq, identity, lambda x: x - 1)
+    ti.set_finished_dependency(3)
+    ti.register_tasks((4, 5))
+    ti.finish_prereq(OnePrereq.one, (4, ))
+    ti.finish_prereq(OnePrereq.one, (5, ))
+
+    completed = await wait(ti.ready_tasks())
+    assert completed == (4, 5)
+
+
+@pytest.mark.asyncio
+async def test_pruning():
+    # make a number task depend on the mod10, so 4 and 14 both depend on task 3
+    ti = OrderedTaskPreparation(OnePrereq, identity, lambda x: (x % 10) - 1, max_depth=2)
+    ti.set_finished_dependency(3)
+    ti.register_tasks((4, 5, 6))
+    ti.finish_prereq(OnePrereq.one, (4, 5, 6))
+
+    # it's fine to prepare a task that depends up to two back in history
+    # this depends on 5
+    ti.register_tasks((16, ))
+    # this depends on 4
+    ti.register_tasks((15, ))
+
+    # but depending 3 back in history should raise a validation error, because it's pruned
+    with pytest.raises(ValidationError):
+        # this depends on 3
+        ti.register_tasks((14, ))
+
+    # test the same concept, but after pruning more than just the starting task...
+    ti.register_tasks((7, ))
+    ti.finish_prereq(OnePrereq.one, (7, ))
+
+    ti.register_tasks((16, ))
+    ti.register_tasks((17, ))
+    with pytest.raises(ValidationError):
+        ti.register_tasks((15, ))
+
+
+@pytest.mark.asyncio
+async def test_wait_forever():
+    ti = OrderedTaskPreparation(OnePrereq, identity, lambda x: x - 1)
+    try:
+        finished = await wait(ti.ready_tasks())
+    except asyncio.TimeoutError:
+        pass
+    else:
+        assert False, f"No steps should complete, but got {finished!r}"
+
+
+def test_finish_same_task_twice():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    ti.set_finished_dependency(1)
+    ti.register_tasks((2, ))
+    ti.finish_prereq(TwoPrereqs.Prereq1, (2,))
+    with pytest.raises(ValidationError):
+        ti.finish_prereq(TwoPrereqs.Prereq1, (2,))
+
+
+@pytest.mark.asyncio
+async def test_finish_different_entry_at_same_step():
+
+    def previous_even_number(num):
+        return ((num - 1) // 2) * 2
+
+    ti = OrderedTaskPreparation(OnePrereq, identity, previous_even_number)
+
+    ti.set_finished_dependency(2)
+
+    ti.register_tasks((3, 4))
+
+    # depends on 2
+    ti.finish_prereq(OnePrereq.one, (3,))
+
+    # also depends on 2
+    ti.finish_prereq(OnePrereq.one, (4,))
+
+    completed = await wait(ti.ready_tasks())
+    assert completed == (3, 4)
+
+
+@pytest.mark.asyncio
+async def test_return_original_entry():
+    # for no particular reason, the id is 3 before the number
+    ti = OrderedTaskPreparation(OnePrereq, lambda x: x - 3, lambda x: x - 4)
+
+    # translates to id -1
+    ti.set_finished_dependency(2)
+
+    ti.register_tasks((3, 4))
+
+    # translates to id 0
+    ti.finish_prereq(OnePrereq.one, (3,))
+
+    # translates to id 1
+    ti.finish_prereq(OnePrereq.one, (4,))
+
+    entries = await wait(ti.ready_tasks())
+
+    # make sure that the original task is returned, not the id
+    assert entries == (3, 4)
+
+
+def test_finish_with_unrecognized_task():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    ti.set_finished_dependency(1)
+    with pytest.raises(ValidationError):
+        ti.finish_prereq('UNRECOGNIZED_TASK', (2,))
+
+
+def test_finish_before_setting_start_val():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    with pytest.raises(ValidationError):
+        ti.finish_prereq(TwoPrereqs.Prereq1, (2,))
+
+
+def test_finish_too_early():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    ti.set_finished_dependency(3)
+    with pytest.raises(ValidationError):
+        ti.finish_prereq(TwoPrereqs.Prereq1, (3,))
+
+
+def test_empty_completion():
+    ti = OrderedTaskPreparation(TwoPrereqs, identity, lambda x: x - 1)
+    with pytest.raises(ValidationError):
+        ti.finish_prereq(TwoPrereqs.Prereq1, tuple())
+
+
+def test_empty_enum():
+
+    class NoPrerequisites(Enum):
+        pass
+
+    with pytest.raises(ValidationError):
+        OrderedTaskPreparation(NoPrerequisites, identity, lambda x: x - 1)