chore: import upstream snapshot with attribution

tests/test_engine/test_compaction_control.py

@@ -0,0 +1,80 @@
+from __future__ import annotations
+
+from opensquilla.engine.compaction_control import decide_compaction_continuation
+
+
+def test_valid_compaction_receipt_continues_when_prompt_changed() -> None:
+    decision = decide_compaction_continuation(
+        receipt_safe=True,
+        raw_session_durable=True,
+        semantic_flush_ok=True,
+        retry_count=0,
+        max_retries=1,
+        prompt_changed=True,
+        finalization_attempted=False,
+    )
+
+    assert decision.action == "continue_after_compaction"
+
+
+def test_semantic_flush_degradation_degrades_when_raw_session_is_durable() -> None:
+    decision = decide_compaction_continuation(
+        receipt_safe=True,
+        raw_session_durable=True,
+        semantic_flush_ok=False,
+        retry_count=1,
+        max_retries=1,
+        prompt_changed=False,
+        finalization_attempted=False,
+    )
+
+    assert decision.action == "degraded_continue_after_compaction"
+
+
+def test_unsafe_receipt_blocks_as_context_unsalvageable() -> None:
+    decision = decide_compaction_continuation(
+        receipt_safe=False,
+        raw_session_durable=True,
+        semantic_flush_ok=True,
+        retry_count=0,
+        max_retries=1,
+        prompt_changed=True,
+        finalization_attempted=False,
+    )
+
+    assert decision.action == "blocked_after_compaction"
+    assert decision.reason == "context_unsalvageable"
+
+
+def test_retries_before_partial_or_failed_compaction_result() -> None:
+    retry = decide_compaction_continuation(
+        receipt_safe=True,
+        raw_session_durable=True,
+        semantic_flush_ok=True,
+        retry_count=0,
+        max_retries=1,
+        prompt_changed=False,
+        finalization_attempted=False,
+    )
+    partial = decide_compaction_continuation(
+        receipt_safe=True,
+        raw_session_durable=True,
+        semantic_flush_ok=True,
+        retry_count=1,
+        max_retries=1,
+        prompt_changed=False,
+        finalization_attempted=False,
+    )
+    failed = decide_compaction_continuation(
+        receipt_safe=True,
+        raw_session_durable=True,
+        semantic_flush_ok=True,
+        retry_count=1,
+        max_retries=1,
+        prompt_changed=False,
+        finalization_attempted=True,
+    )
+
+    assert retry.action == "retry_after_compaction"
+    assert partial.action == "partial_after_compaction"
+    assert failed.action == "failed_after_compaction"