[F018] claim_guards: treat blocked as active + broaden the guard lookup so a blocked dev can't double-claim

tests/unit/gateway/test_claim_guards_blocked.py

@@ -0,0 +1,57 @@
+"""F018 — ``already_active_guard`` must treat a ``blocked`` task as active.
+
+``_ACTIVE_BLOCKING_STATUSES`` excluded ``blocked``, so a developer with a
+blocked task could claim a second task (the guard passed). When the blocked
+task was later unblocked via ``unblock_with_restore`` it resumed to
+``in_progress`` — leaving the dev silently holding TWO ``in_progress`` tasks,
+violating the one-active-task-per-dev invariant the guard exists to enforce.
+A blocked task is still owned and will resume to active, so it must block a
+new claim.
+"""
+
+from __future__ import annotations
+
+from unittest.mock import MagicMock
+from uuid import uuid4
+
+from roboco.services.gateway.claim_guards import already_active_guard
+
+
+def _task(*, status: str) -> MagicMock:
+    t = MagicMock()
+    t.id = uuid4()
+    t.status = status
+    return t
+
+
+def test_already_active_guard_blocks_when_agent_has_blocked_task() -> None:
+    """A blocked task the dev still owns must block a new claim (F018)."""
+    target_id = uuid4()
+    blocked = _task(status="blocked")
+    env = already_active_guard([blocked], target_id)
+    assert env is not None
+    assert env.error == "invalid_state"
+
+
+def test_already_active_guard_still_blocks_in_progress() -> None:
+    """Regression: the existing in_progress case still fires."""
+    target_id = uuid4()
+    in_progress = _task(status="in_progress")
+    env = already_active_guard([in_progress], target_id)
+    assert env is not None
+
+
+def test_already_active_guard_excludes_target_task_itself() -> None:
+    """Re-claiming/resuming the same blocked task must not self-block."""
+    target_id = uuid4()
+    blocked_self = MagicMock(id=target_id, status="blocked")
+    env = already_active_guard([blocked_self], target_id)
+    assert env is None
+
+
+def test_already_active_guard_passes_when_no_active_tasks() -> None:
+    """A dev with only terminal/backlog tasks may claim."""
+    target_id = uuid4()
+    others = [_task(status="completed"), _task(status="backlog")]
+    env = already_active_guard(others, target_id)
+    assert env is None