mirror of
https://github.com/turnstonelabs/turnstone.git
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Patrick Buckley
74f1958e47
Adds an atomic drop-oldest-by-type operation to NudgeQueue used by producers that need a per-type soft cap on their own queue depth. The watch dispatcher (next commit in this stack) is the first user: when "watch_triggered" saturates, the dispatch closure drops its oldest entry under the queue lock so the count snapshot and drop can't interleave with a concurrent enqueue from the same producer. Implements watch-switchover plan section 3.1 — the producer-side soft cap takes the place of the deleted _watch_pending maxsize=20 bound. Other producers (idle_children, advisories) have natural rate limiters already, so the helper is opt-in per producer rather than a global cap in enqueue itself.
344 lines
12 KiB
Python
344 lines
12 KiB
Python
"""Unit tests for :class:`NudgeQueue`."""
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from __future__ import annotations
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import threading
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import pytest
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from turnstone.core.nudge_queue import TOOL_DRAIN, USER_DRAIN, NudgeQueue
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class TestEnqueueDrain:
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def test_enqueue_drain_fifo_order(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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q.enqueue("c", "3", "any")
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# Drain everything regardless of channel — preserves insertion order.
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out = q.drain({"user", "tool", "any"})
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assert out == [("a", "1"), ("b", "2"), ("c", "3")]
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assert len(q) == 0
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def test_drain_filter_keeps_non_matching(self):
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q = NudgeQueue()
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q.enqueue("a", "x", "user")
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q.enqueue("b", "y", "tool")
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# Drain only user → tool entry stays.
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out = q.drain(USER_DRAIN)
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assert out == [("a", "x")]
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assert len(q) == 1
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# Now drain tool — gets the remaining entry.
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out = q.drain(TOOL_DRAIN)
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assert out == [("b", "y")]
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assert len(q) == 0
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def test_any_channel_drains_on_either_seam(self):
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q = NudgeQueue()
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q.enqueue("c", "z", "any")
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# User-seam drain pulls "any".
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assert q.drain(USER_DRAIN) == [("c", "z")]
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assert len(q) == 0
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# Re-enqueue and prove tool-seam also drains "any".
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q.enqueue("d", "w", "any")
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assert q.drain(TOOL_DRAIN) == [("d", "w")]
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assert len(q) == 0
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def test_drain_empty_filter_no_op(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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# Empty filter drains nothing.
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assert q.drain(set()) == []
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assert len(q) == 1
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def test_drain_empty_queue_returns_empty_list(self):
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q = NudgeQueue()
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# Fast-path: no items → no kept-deque allocation, just `[]`.
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assert q.drain(USER_DRAIN) == []
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assert q.drain({"user", "tool", "any"}) == []
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assert len(q) == 0
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def test_drain_preserves_order_across_partial_drain(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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q.enqueue("c", "3", "user")
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q.enqueue("d", "4", "tool")
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# Drain user — should get "a" then "c" in order; "b","d" stay.
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assert q.drain({"user"}) == [("a", "1"), ("c", "3")]
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# Tool drain follows insertion order on remaining.
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assert q.drain({"tool"}) == [("b", "2"), ("d", "4")]
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class TestLenAndClear:
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def test_len_does_not_mutate(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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assert len(q) == 1
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assert len(q) == 1 # second call still 1; not consumed
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assert q.pending() == [("a", "1")]
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def test_len_empty_is_zero(self):
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q = NudgeQueue()
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assert len(q) == 0
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def test_clear_returns_count(self):
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q = NudgeQueue()
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assert q.clear() == 0
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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q.enqueue("c", "3", "any")
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assert q.clear() == 3
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assert len(q) == 0
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def test_clear_empty_returns_zero(self):
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q = NudgeQueue()
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assert q.clear() == 0
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class TestDropOldestByType:
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def test_drop_oldest_by_type_removes_earliest_match(self):
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"""Drop the FIRST entry of the matching type; later matches stay."""
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q = NudgeQueue()
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q.enqueue("other", "first", "any")
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q.enqueue("target", "older", "any")
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q.enqueue("target", "newer", "any")
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# "older" is the earliest target — drop it.
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assert q.drop_oldest_by_type("target") is True
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assert q.pending() == [("other", "first"), ("target", "newer")]
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def test_drop_oldest_by_type_no_match_returns_false(self):
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"""Empty queue and unmatched-type cases both return False."""
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q = NudgeQueue()
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# Empty.
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assert q.drop_oldest_by_type("target") is False
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# Non-matching items only.
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q.enqueue("other", "1", "any")
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q.enqueue("other", "2", "tool")
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assert q.drop_oldest_by_type("target") is False
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# Queue is unaffected.
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assert q.pending() == [("other", "1"), ("other", "2")]
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def test_drop_oldest_by_type_only_drops_one(self):
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"""Multiple matching entries → only the first is removed."""
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q = NudgeQueue()
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q.enqueue("target", "1", "any")
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q.enqueue("target", "2", "any")
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q.enqueue("target", "3", "any")
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assert q.drop_oldest_by_type("target") is True
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assert q.pending() == [("target", "2"), ("target", "3")]
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class TestPending:
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def test_pending_no_filter_returns_all_in_order(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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q.enqueue("c", "3", "any")
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# All three, in insertion order, as (nudge_type, text) tuples.
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assert q.pending() == [("a", "1"), ("b", "2"), ("c", "3")]
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def test_pending_channel_filter(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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q.enqueue("c", "3", "user")
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q.enqueue("d", "4", "any")
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assert q.pending("user") == [("a", "1"), ("c", "3")]
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assert q.pending("tool") == [("b", "2")]
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assert q.pending("any") == [("d", "4")]
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def test_pending_does_not_mutate(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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# Two pending calls return same content; nothing consumed.
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first = q.pending()
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second = q.pending()
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assert first == second
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assert len(q) == 2
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class TestHasPending:
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def test_has_pending_returns_false_on_empty_queue(self):
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q = NudgeQueue()
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assert q.has_pending({"user", "any"}) is False
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assert q.has_pending({"tool"}) is False
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def test_has_pending_short_circuits_on_first_match(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "tool")
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q.enqueue("b", "2", "user")
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# First entry doesn't match, second does — true after walking 2.
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assert q.has_pending({"user"}) is True
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def test_has_pending_returns_false_when_no_match(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "tool")
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q.enqueue("b", "2", "tool")
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assert q.has_pending({"user", "any"}) is False
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def test_has_pending_matches_any_channel(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "any")
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# USER_DRAIN-shaped filter pulls "any" entries.
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assert q.has_pending(USER_DRAIN) is True
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# TOOL_DRAIN-shaped filter also pulls "any" entries.
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assert q.has_pending(TOOL_DRAIN) is True
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def test_has_pending_does_not_mutate(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "user")
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q.enqueue("b", "2", "tool")
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before = q.pending()
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q.has_pending({"user"})
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q.has_pending({"tool"})
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q.has_pending(set())
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assert q.pending() == before
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class TestValidation:
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def test_invalid_channel_raises(self):
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q = NudgeQueue()
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with pytest.raises(ValueError, match="channel"):
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q.enqueue("a", "1", "wake") # type: ignore[arg-type]
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with pytest.raises(ValueError):
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q.enqueue("b", "2", "") # type: ignore[arg-type]
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# Queue is unaffected by the failed enqueues.
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assert len(q) == 0
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def test_channel_is_required(self):
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q = NudgeQueue()
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# No default — caller MUST pick a seam consciously.
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with pytest.raises(TypeError):
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q.enqueue("a", "1") # type: ignore[call-arg]
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class TestValidUntil:
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"""``valid_until`` predicate: drain re-checks freshness; falsy /
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raising predicates drop the entry without delivery.
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"""
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def test_valid_until_true_delivers(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "any", valid_until=lambda: True)
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out = q.drain({"any"})
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assert out == [("a", "1")]
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def test_valid_until_false_drops_silently(self):
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q = NudgeQueue()
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q.enqueue("a", "1", "any", valid_until=lambda: False)
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out = q.drain({"any"})
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assert out == []
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# Already removed from queue (drain partition removes BEFORE
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# predicate check — falsy doesn't return to queue).
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assert len(q) == 0
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def test_valid_until_exception_drops_silently(self):
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q = NudgeQueue()
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def boom() -> bool:
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raise RuntimeError("predicate crash")
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q.enqueue("a", "1", "any", valid_until=boom)
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out = q.drain({"any"})
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assert out == []
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# Crash-on-predicate is treated as "no longer valid" — drop, not propagate.
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assert len(q) == 0
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def test_valid_until_evaluated_outside_lock(self):
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"""The predicate may do non-trivial work (e.g. storage I/O)
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without blocking other producers. Verify the predicate runs
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outside the queue's internal lock by enqueueing from inside
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the predicate — would deadlock if the lock was still held.
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"""
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q = NudgeQueue()
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def reentrant() -> bool:
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# If the lock is held during predicate eval, this enqueue
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# would block forever (RLock would let it through, but the
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# queue uses a plain Lock).
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q.enqueue("inner", "from-predicate", "any", valid_until=lambda: True)
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return True
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q.enqueue("outer", "1", "any", valid_until=reentrant)
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out = q.drain({"any"})
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# Outer's predicate ran outside the lock, enqueued "inner";
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# outer's True return delivered "outer". "inner" was enqueued
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# AFTER the partition snapshot, so it stays in the queue.
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assert out == [("outer", "1")]
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assert q.pending() == [("inner", "from-predicate")]
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def test_valid_until_only_evaluated_for_matching_channel(self):
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"""A non-matching entry's predicate must NOT fire — that would
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be wasted work (or worse, a side-effecting predicate would run
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when the entry is supposed to stay queued).
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"""
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q = NudgeQueue()
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calls = []
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def track() -> bool:
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calls.append(1)
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return True
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# Tool-channel entry; we drain user-channel. Predicate must not run.
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q.enqueue("a", "1", "tool", valid_until=track)
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q.drain({"user", "any"})
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assert calls == []
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# Entry stays queued.
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assert q.pending("tool") == [("a", "1")]
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def test_valid_until_default_none_always_delivers(self):
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# No predicate → entry behaves identically to pre-PR-3 entries.
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q = NudgeQueue()
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q.enqueue("a", "1", "any") # no valid_until kwarg
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assert q.drain({"any"}) == [("a", "1")]
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class TestConcurrency:
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def test_concurrent_enqueue_drain_no_loss(self):
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"""16 producer threads × 64 nudges = 1024 total; one consumer
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drains in a loop until producers finish + queue empty. Verify
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every produced item is observed exactly once.
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"""
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q = NudgeQueue()
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producers = 16
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per_producer = 64
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total = producers * per_producer
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produced: set[tuple[str, str]] = set()
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produced_lock = threading.Lock()
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observed: list[tuple[str, str]] = []
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observed_lock = threading.Lock()
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done_event = threading.Event()
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def produce(pid: int) -> None:
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for i in range(per_producer):
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key = (f"p{pid}", f"i{i}")
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with produced_lock:
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produced.add(key)
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q.enqueue(key[0], key[1], "user")
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def consume() -> None:
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while not done_event.is_set() or len(q) > 0:
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drained = q.drain({"user"})
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if drained:
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with observed_lock:
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observed.extend(drained)
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consumer = threading.Thread(target=consume, daemon=True)
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consumer.start()
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threads = [threading.Thread(target=produce, args=(i,)) for i in range(producers)]
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for t in threads:
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t.start()
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for t in threads:
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t.join()
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done_event.set()
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consumer.join(timeout=5.0)
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assert not consumer.is_alive(), "consumer didn't finish in time"
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# Every produced key observed; no duplicates.
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assert set(observed) == produced
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assert len(observed) == total
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assert len(q) == 0
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