feat(memory): add incremental transcript compaction

tests/unit/memory/test_context_policy.py

@@ -0,0 +1,304 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""ContextPolicy table (M4): byte-exact parity with the eight historical call
+sites, config overrides, and the chunk hand-off to the compiled view."""
+
+from types import SimpleNamespace
+from unittest.mock import patch
+
+import pytest
+
+from artemis.memory.context_policy import (
+    CONTEXT_POLICIES,
+    DIGEST_LEDGER_MARKER_TEMPLATE,
+    build_history_for,
+    load_chunk_blocks,
+    resolve_policy,
+)
+from artemis.utils.task_tree import build_plan_and_history
+
+HASH_A = "hash-a"
+HASH_B = "hash-b"
+
+TASK_PLAN = f"- [x] First milestone <!-- {HASH_A} -->\n- [/] Second milestone <!-- {HASH_B} -->"
+
+
+def _step(number: int, subgoal_hash: str, summary: str | None = None) -> dict:
+    return {
+        "step_id": f"id-{number}",
+        "step_number": number,
+        "relative_time": f"{number * 10}.0s",
+        "summary": summary or f"Step {number} summary text.",
+        "action_taken": {"action": "click", "target_text": f"button {number}"},
+        "operator_raw_thinking": f"thinking {number}",
+        "last_execution_result": {"status": "success"},
+        "extra_metadata": {"subgoal_hash": subgoal_hash},
+    }
+
+
+STEPS = [
+    _step(1, HASH_A),
+    _step(2, HASH_A),
+    _step(3, HASH_A),
+    _step(4, HASH_B),
+    _step(5, HASH_B),
+    _step(6, HASH_B),
+    _step(7, HASH_B),
+]
+
+
+# ---------------------------------------------------------------------------
+# Golden parity: the policy table must reproduce every historical hard-coded
+# call byte for byte (kwargs recorded verbatim from the 2026-09-01 call sites).
+# ---------------------------------------------------------------------------
+
+
+GOLDEN_CALLS = {
+    "operator": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        last_n_detailed=1,
+        strict_milestone_pruning=True,
+        recent_window_size=3,
+    ),
+    "operator_cold_start": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        min_summaries=len(STEPS),
+        last_n_detailed=1,
+    ),
+    "failure_analyzer": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        last_n_detailed=1,
+        strict_milestone_pruning=True,
+        recent_window_size=3,
+        for_failure_analyzer=True,
+    ),
+    "planner": lambda: build_plan_and_history(
+        "",
+        STEPS,
+        "default",
+        last_n_detailed=2,
+        strict_milestone_pruning=True,
+        recent_window_size=5,
+    ),
+    "outputter": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        last_n_detailed=0,
+        min_summaries=len(STEPS),
+        strict_milestone_pruning=False,
+    ),
+    "history_analyzer": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        last_n_detailed=1,
+        min_summaries=len(STEPS),
+    ),
+    "diagnoser": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        keep_subgoal_hashes={HASH_B},
+    ),
+    "committee": lambda: build_plan_and_history(
+        TASK_PLAN,
+        STEPS,
+        HASH_B,
+        keep_subgoal_hashes={HASH_B},
+        last_n_detailed=3,
+    ),
+}
+
+POLICY_CALLS = {
+    "operator": lambda: build_history_for(
+        "operator", TASK_PLAN, STEPS, HASH_B, last_n_detailed=1
+    ),
+    "operator_cold_start": lambda: build_history_for(
+        "operator_cold_start", TASK_PLAN, STEPS, HASH_B
+    ),
+    "failure_analyzer": lambda: build_history_for(
+        "failure_analyzer", TASK_PLAN, STEPS, HASH_B
+    ),
+    "planner": lambda: build_history_for("planner", "", STEPS, "default"),
+    "outputter": lambda: build_history_for("outputter", TASK_PLAN, STEPS, HASH_B),
+    "history_analyzer": lambda: build_history_for(
+        "history_analyzer", TASK_PLAN, STEPS, HASH_B
+    ),
+    "diagnoser": lambda: build_history_for(
+        "diagnoser", TASK_PLAN, STEPS, HASH_B, keep_subgoal_hashes={HASH_B}
+    ),
+    "committee": lambda: build_history_for(
+        "committee", TASK_PLAN, STEPS, HASH_B, keep_subgoal_hashes={HASH_B}
+    ),
+}
+
+
+@pytest.mark.parametrize("agent", sorted(GOLDEN_CALLS))
+def test_policy_table_reproduces_call_site_bytes(agent):
+    assert POLICY_CALLS[agent]() == GOLDEN_CALLS[agent]()
+
+
+def test_every_declared_policy_is_golden_tested():
+    assert set(GOLDEN_CALLS) == set(CONTEXT_POLICIES)
+
+
+# ---------------------------------------------------------------------------
+# Config overrides
+# ---------------------------------------------------------------------------
+
+
+def _config_with_policies(policies):
+    return SimpleNamespace(memory=SimpleNamespace(policies=policies))
+
+
+def test_resolve_policy_applies_config_override():
+    cfg = _config_with_policies({"planner": {"last_n_detailed": 3, "bogus_field": 1}})
+    with patch("artemis.config.load_agent_config", return_value=cfg):
+        policy = resolve_policy("planner")
+    assert policy.last_n_detailed == 3
+    assert policy.strict_milestone_pruning is True  # untouched fields survive
+
+
+def test_resolve_policy_unknown_agent_raises():
+    with pytest.raises(KeyError):
+        resolve_policy("no_such_agent")
+
+
+# ---------------------------------------------------------------------------
+# Chunk hand-off (§10 decision 4)
+# ---------------------------------------------------------------------------
+
+
+RENDERED_CHUNK = (
+    "[Chunk 1 | Steps 1–3 | T+00:10 → T+00:30]\n"
+    "\n"
+    "① Synopsis & effects\n"
+    "  What this segment was doing: warming up.\n"
+    "\n"
+    "② Compressed step summary\n"
+    "  - Steps 1–3: opened the app and logged in\n"
+    "\n"
+    "③ Step action ledger\n"
+    "- Step 1 (T+00:10): click['button 1'] -> executed\n"
+    "- Step 2 (T+00:20): click['button 2'] -> executed\n"
+    "- Step 3 (T+00:30): click['button 3'] -> executed"
+)
+
+
+class _FakeEngine:
+    def __init__(self, rows):
+        self._rows = rows
+
+    def get_history_chunks(self, **kwargs):
+        return self._rows
+
+
+def _chunk_row():
+    return SimpleNamespace(
+        start_step_number=1,
+        end_step_number=3,
+        rendered_text=RENDERED_CHUNK,
+        status="ready",
+    )
+
+
+def _transcript_cfg(enabled: bool):
+    return SimpleNamespace(
+        memory=SimpleNamespace(
+            transcript=SimpleNamespace(enabled=enabled), policies={}
+        )
+    )
+
+
+def test_flag_off_output_is_byte_identical_even_with_engine():
+    engine = _FakeEngine([_chunk_row()])
+    with patch("artemis.config.load_agent_config", return_value=_transcript_cfg(False)):
+        with_engine = build_history_for(
+            "outputter", TASK_PLAN, STEPS, HASH_B, engine=engine
+        )
+        without_engine = build_history_for("outputter", TASK_PLAN, STEPS, HASH_B)
+    assert with_engine == without_engine
+    assert "[Chunk 1" not in with_engine
+
+
+def test_flag_on_full_view_renders_chunk_block_and_drops_covered_steps():
+    engine = _FakeEngine([_chunk_row()])
+    with patch("artemis.config.load_agent_config", return_value=_transcript_cfg(True)):
+        out = build_history_for("outputter", TASK_PLAN, STEPS, HASH_B, engine=engine)
+    # Full view: the whole three-band block including the ③ ledger.
+    assert "[Chunk 1 | Steps 1–3" in out
+    assert "③ Step action ledger" in out
+    assert "- Step 2 (T+00:20)" in out
+    # Covered per-step summary lines are replaced by the chunk block.
+    assert "*Step 2 (Start: 20.0s)" not in out
+    # Steps outside the chunk range still render.
+    assert "Step 5" in out
+
+
+def test_flag_on_digest_view_replaces_ledger_with_recall_marker():
+    engine = _FakeEngine([_chunk_row()])
+    cfg = _transcript_cfg(True)
+    with patch("artemis.config.load_agent_config", return_value=cfg):
+        out = build_history_for(
+            "diagnoser",
+            TASK_PLAN,
+            STEPS,
+            HASH_B,
+            keep_subgoal_hashes={HASH_A, HASH_B},
+            engine=engine,
+        )
+    assert "[Chunk 1 | Steps 1–3" in out
+    assert "② Compressed step summary" in out
+    marker = DIGEST_LEDGER_MARKER_TEMPLATE.format(start=1, end=3)
+    assert marker in out
+    assert "- Step 2 (T+00:20)" not in out  # digest carries no ③ rows
+
+
+def test_chunk_view_none_never_loads_chunks():
+    engine = _FakeEngine([_chunk_row()])
+    with patch("artemis.config.load_agent_config", return_value=_transcript_cfg(True)):
+        assert load_chunk_blocks(engine, None) is None
+        # The cold-start policy declares chunk_view=None: even with an engine
+        # and the flag on, its output carries no chunk blocks (the restored
+        # F region must stay a pure step rendering).
+        out = build_history_for(
+            "operator_cold_start", TASK_PLAN, STEPS, HASH_B, engine=engine
+        )
+    assert CONTEXT_POLICIES["operator_cold_start"].chunk_view is None
+    assert "[Chunk 1" not in out
+
+
+def test_most_recent_step_is_never_suppressed_by_a_chunk():
+    engine = _FakeEngine(
+        [
+            SimpleNamespace(
+                start_step_number=1,
+                end_step_number=7,  # covers every step incl. the newest
+                rendered_text=RENDERED_CHUNK,
+                status="ready",
+            )
+        ]
+    )
+    with patch("artemis.config.load_agent_config", return_value=_transcript_cfg(True)):
+        out = build_history_for("outputter", TASK_PLAN, STEPS, HASH_B, engine=engine)
+    # The most-recent step must keep its own (detailed) rendering.
+    assert "Step 7" in out