tests/runtime/test_io.py

from proteus.game.agents import VanillaAgent
from proteus.providers import FakeProvider
from proteus.game.runtime import SessionRunner, append_trace, read_traces


def _trace(seed):
    agent = VanillaAgent(FakeProvider(responses=["ACTION: up"], model_name="fake-1"))
    return SessionRunner(
        "template", agent, seed=seed, play_turns=4, use_probe=False,
    ).run()


def test_append_then_read_roundtrips_one_trace(tmp_path):
    path = tmp_path / "runs" / "session.jsonl"
    written = append_trace(_trace(42), path)
    assert written.exists()
    traces = read_traces(path)
    assert len(traces) == 1
    assert traces[0].scenario == "template"
    assert traces[0].model == "fake-1"


def test_append_accumulates_multiple_sessions(tmp_path):
    path = tmp_path / "session.jsonl"
    append_trace(_trace(1), path)
    append_trace(_trace(2), path)
    traces = read_traces(path)
    assert len(traces) == 2
    assert [t.seed for t in traces] == [1, 2]


def test_read_ignores_blank_lines(tmp_path):
    path = tmp_path / "s.jsonl"
    append_trace(_trace(7), path)
    with path.open("a", encoding="utf-8") as f:
        f.write("\n")  # trailing blank line
    assert len(read_traces(path)) == 1


def test_append_creates_parent_dirs(tmp_path):
    path = tmp_path / "deep" / "nested" / "s.jsonl"
    append_trace(_trace(3), path)
    assert path.exists()