Files
turnstone/tests/test_tool_truncation.py
T
Patrick Buckley dc88060b79 refactor(core): session.messages is the canonical Turn trajectory
ChatSession.messages flips from list[dict] to list[Turn] — the in-memory
canonical trajectory.  Reads migrate to typed fields (turn.role, turn.text,
turn.tool_calls); appends and assignments go through turn_from_dict /
turns_from_dicts; the fork bulk-save and retry's multipart check read via
turn_to_dict.  _full_messages lowers Turns→dicts at the wire boundary — the
fold/repair and provider translators still consume dicts until the next slice.
The token-accounting helpers accept a dict or a Turn.

Non-session consumers migrate too: coordinator_idle_observer and eval to typed
fields (mypy-enumerated), and server's last-assistant extractor via turn_to_dict
(an Any-typed call site mypy could not flag).  An all-text multipart content
list (the unreadable-attachment placeholder path) now round-trips faithfully
through the adapter (single text block → str, multiple → list).

Tests that inspected session.messages as dicts read it through the
dicts_from_turns / turn_to_dict bridge; those that built it pass dicts through
turns_from_dicts / turn_from_dict.  Byte-identical wire harness; full non-live
suite green (7130).
2026-06-04 11:03:13 -07:00

242 lines
8.9 KiB
Python

"""Tests for capacity-aware tool output truncation and context overflow recovery."""
from __future__ import annotations
from unittest.mock import MagicMock, patch
import pytest
from turnstone.core.session import ChatSession
from turnstone.core.trajectory import turns_from_dicts
# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------
@pytest.fixture
def session(tmp_db, mock_openai_client):
"""Create a ChatSession with defaults for truncation testing."""
return ChatSession(
client=mock_openai_client,
model="test-model",
ui=MagicMock(),
instructions=None,
temperature=0.5,
tool_timeout=10,
context_window=10_000,
max_tokens=1_000,
)
# ---------------------------------------------------------------------------
# _truncate_output
# ---------------------------------------------------------------------------
class TestTruncateOutput:
def test_no_truncation_when_under_limit(self, session):
result = session._truncate_output("short text")
assert result == "short text"
def test_truncates_to_tool_truncation_limit(self, session):
session.tool_truncation = 100
big = "x" * 500
result = session._truncate_output(big)
assert len(result) <= 200 # head + tail + marker
assert "chars truncated" in result
def test_budget_aware_truncation(self, session):
session.tool_truncation = 100_000
session._chars_per_token = 4.0
# Budget of 50 tokens = 200 chars
big = "x" * 1000
result = session._truncate_output(big, remaining_budget_tokens=50)
assert len(result) <= 400 # head + tail + marker
assert "chars truncated" in result
def test_budget_takes_precedence_when_smaller(self, session):
session.tool_truncation = 10_000
session._chars_per_token = 4.0
# Budget of 25 tokens = 100 chars, smaller than tool_truncation
big = "x" * 500
result = session._truncate_output(big, remaining_budget_tokens=25)
assert "chars truncated" in result
def test_zero_budget_returns_placeholder(self, session):
big = "x" * 1000
result = session._truncate_output(big, remaining_budget_tokens=0)
assert "exceeded context budget" in result
assert len(result) < 100
def test_negative_budget_returns_placeholder(self, session):
big = "x" * 1000
result = session._truncate_output(big, remaining_budget_tokens=-10)
assert "exceeded context budget" in result
def test_none_budget_uses_fixed_limit(self, session):
session.tool_truncation = 100
big = "x" * 500
result = session._truncate_output(big, remaining_budget_tokens=None)
assert "100 char limit" in result
# ---------------------------------------------------------------------------
# _remaining_token_budget
# ---------------------------------------------------------------------------
class TestRemainingTokenBudget:
def test_empty_session(self, session):
session._system_tokens = 500
session._msg_tokens = []
budget = session._remaining_token_budget()
# 10000 - 500 - 0 - 1000 - 500 (5%) = 8000
assert budget == 8000
def test_partially_full(self, session):
session._system_tokens = 500
session._msg_tokens = [2000, 3000]
budget = session._remaining_token_budget()
# 10000 - 500 - 5000 - 1000 - 500 = 3000
assert budget == 3000
def test_overfull_returns_zero(self, session):
session._system_tokens = 500
session._msg_tokens = [9000]
assert session._remaining_token_budget() == 0
def test_exactly_full_returns_zero(self, session):
session._system_tokens = 500
session._msg_tokens = [8000]
assert session._remaining_token_budget() == 0
def test_max_tokens_equals_context_window(self, tmp_db, mock_openai_client):
"""Regression: max_tokens >= context_window must not zero the budget."""
s = ChatSession(
client=mock_openai_client,
model="test-model",
ui=MagicMock(),
instructions=None,
temperature=0.5,
tool_timeout=10,
context_window=32_768,
max_tokens=32_768,
)
s._system_tokens = 500
s._msg_tokens = [1000]
budget = s._remaining_token_budget()
# response_reserve = min(32768, 32768//4) = 8192
# safety = 32768 * 0.05 = 1638
# budget = 32768 - 500 - 1000 - 8192 - 1638 = 21438
assert budget > 20_000
# Tool output should NOT be collapsed to a placeholder
big = "x" * 5000
result = s._truncate_output(big, remaining_budget_tokens=budget)
assert result == big # 5000 chars fits easily in 21K+ token budget
# ---------------------------------------------------------------------------
# Context overflow recovery
# ---------------------------------------------------------------------------
class TestContextOverflowRecovery:
"""Test that context-length errors trigger compact-and-retry."""
def test_openai_context_length_error_triggers_compact(self, session):
session.messages = turns_from_dicts([{"role": "user", "content": "hi"}])
session._msg_tokens = [1]
call_count = 0
def mock_create_stream(msgs):
nonlocal call_count
call_count += 1
if call_count == 1:
raise Exception("maximum context length exceeded")
return iter([])
compact_mock = MagicMock()
with (
patch.object(session, "_create_stream_with_retry", side_effect=mock_create_stream),
patch.object(session, "_compact_messages", compact_mock),
patch.object(
session, "_stream_response", return_value={"role": "assistant", "content": "ok"}
),
patch.object(session, "_full_messages", return_value=[]),
patch.object(session, "_update_token_table"),
patch.object(session, "_print_status_line"),
patch.object(session, "_emit_state"),
patch("turnstone.core.session.save_message"),
):
session.send("hello")
compact_mock.assert_called_once_with(auto=True)
assert call_count == 2
def test_anthropic_prompt_too_long_triggers_compact(self, session):
session.messages = turns_from_dicts([{"role": "user", "content": "hi"}])
session._msg_tokens = [1]
call_count = 0
def mock_create_stream(msgs):
nonlocal call_count
call_count += 1
if call_count == 1:
raise Exception("prompt is too long: 250000 tokens > 200000 maximum")
return iter([])
compact_mock = MagicMock()
with (
patch.object(session, "_create_stream_with_retry", side_effect=mock_create_stream),
patch.object(session, "_compact_messages", compact_mock),
patch.object(
session, "_stream_response", return_value={"role": "assistant", "content": "ok"}
),
patch.object(session, "_full_messages", return_value=[]),
patch.object(session, "_update_token_table"),
patch.object(session, "_print_status_line"),
patch.object(session, "_emit_state"),
patch("turnstone.core.session.save_message"),
):
session.send("hello")
compact_mock.assert_called_once_with(auto=True)
def test_non_context_error_propagates(self, session):
session.messages = turns_from_dicts([{"role": "user", "content": "hi"}])
session._msg_tokens = [1]
with (
patch.object(
session,
"_create_stream_with_retry",
side_effect=Exception("authentication failed"),
),
patch.object(session, "_full_messages", return_value=[]),
patch.object(session, "_emit_state"),
patch("turnstone.core.session.save_message"),
pytest.raises(Exception, match="authentication failed"),
):
session.send("hello")
def test_compact_failure_raises_original_error(self, session):
session.messages = turns_from_dicts([{"role": "user", "content": "hi"}])
session._msg_tokens = [1]
with (
patch.object(
session,
"_create_stream_with_retry",
side_effect=Exception("maximum context length exceeded"),
),
patch.object(session, "_compact_messages", side_effect=RuntimeError("compact failed")),
patch.object(session, "_full_messages", return_value=[]),
patch.object(session, "_emit_state"),
patch("turnstone.core.session.save_message"),
pytest.raises(Exception, match="maximum context length exceeded"),
):
session.send("hello")