interactive-story/backend/tests/test_take_state.py

"""Phase 14 SP9 — what a take does to the shared state.

A turn does not only write text. A script mutates `script_state`, the referee
mutates `world_state`, and both are *shared* — they belong to the adventure, not
to the node. So playing a turn again has to put them back to where they were
before that turn ran, or the new take stacks its mutations on top of the one it
replaces and the numbers drift every time the player asks for another take.

`retry` has done this since SP4 (`attempts.roll_back_before`). These are the
same guarantee for the two roads SP9 opened: a take of a turn the story moved
past, and a take of the player's own turn. Both create a branch, which is the
interesting part — the rollback has to survive leaving the line it was on.

    python -m pytest tests/test_take_state.py -v
"""
import os
import tempfile

_tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
_tmp.close()
os.environ["AIDND_DB_PATH"] = _tmp.name
os.environ.pop("AIDND_DATABASE_URL", None)
os.environ.pop("DATABASE_URL", None)

import pytest
from fastapi import Depends
from fastapi.testclient import TestClient

from app import auth, limits, models
from app.database import Base, SessionLocal, engine, get_db
from app.main import app
from app.providers import PromptParts
from app.routers import adventures

SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}

# Ten gold a turn, every turn. A number that only ever goes up is the clearest
# possible witness to a rollback: if a take stacks instead of replacing, it says
# so in one digit.
GOLD_SCRIPT = """
const modifier = (text) => {
  state.gold = (state.gold || 0) + 10;
  return { text };
};
modifier(text);
"""


class ScriptedProvider:
    replies: list = []
    calls = 0

    def __init__(self, *a, **k):
        pass

    async def generate(self, parts: PromptParts, *, temperature, max_tokens):
        index = min(ScriptedProvider.calls, len(ScriptedProvider.replies) - 1)
        ScriptedProvider.calls += 1
        yield ("text", ScriptedProvider.replies[index])


@pytest.fixture()
def client(monkeypatch):
    Base.metadata.create_all(bind=engine)
    setup = SessionLocal()
    user = models.User(is_guest=False, email="takestate@example.com")
    setup.add(user)
    setup.flush()
    setup.add(models.Settings(user_id=user.id, api_key="enc:dummy", model="test-model"))
    scenario = models.Scenario(user_id=user.id, title="S", stat_schema=SCHEMA)
    setup.add(scenario)
    setup.flush()
    adv = models.Adventure(
        user_id=user.id, title="Vault", scenario_id=scenario.id,
        script_state={}, world_state={"player": {"hp": 100}},
    )
    setup.add(adv)
    setup.flush()
    setup.add(models.Action(adventure_id=adv.id, index=0, type="start", text="You begin."))
    setup.add(models.AdventureScript(
        adventure_id=adv.id, position=0, enabled=True, name="Gold", output_js=GOLD_SCRIPT,
    ))
    setup.commit()
    adv_id, user_id = adv.id, user.id
    setup.close()

    ScriptedProvider.replies = [f"Take {n}." for n in range(1, 40)]
    ScriptedProvider.calls = 0
    monkeypatch.setattr(adventures, "OpenAICompatibleProvider", ScriptedProvider)
    monkeypatch.setattr(auth, "resolve_provider_config", lambda s: auth.ProviderConfig(
        "http://fake", "k", "test-model", False))
    monkeypatch.setattr(limits, "rate_limit", lambda *a, **k: None)
    monkeypatch.setattr(limits, "check_row_cap", lambda *a, **k: None)

    def _current_user(db=Depends(get_db)):
        return db.get(models.User, user_id)

    app.dependency_overrides[auth.get_current_user] = _current_user
    c = TestClient(app)
    c.adv_id = adv_id
    try:
        yield c
    finally:
        app.dependency_overrides.clear()
        adventures._active_turns.clear()
        Base.metadata.drop_all(bind=engine)


def _play(client, text="look around", after_id=None):
    body = {"type": "do", "text": text}
    if after_id is not None:
        body["after_id"] = after_id
    r = client.post(f"/api/adventures/{client.adv_id}/actions", json=body)
    assert r.status_code == 200, r.text


def _take(client, action_id, text=""):
    r = client.post(
        f"/api/adventures/{client.adv_id}/actions/{action_id}/takes",
        json={"text": text},
    )
    assert r.status_code == 200, r.text
    return r


def _gold(adv_id) -> int:
    db = SessionLocal()
    try:
        return (db.get(models.Adventure, adv_id).script_state or {}).get("gold", 0)
    finally:
        db.close()


def _rows(adv_id, type_):
    db = SessionLocal()
    try:
        return (
            db.query(models.Action)
            .filter(models.Action.adventure_id == adv_id, models.Action.type == type_)
            .order_by(models.Action.id)
            .all()
        )
    finally:
        db.close()


def test_the_script_runs_once_a_turn(client):
    """The premise the rest of the file rests on."""
    _play(client)
    assert _gold(client.adv_id) == 10
    _play(client, "press on")
    assert _gold(client.adv_id) == 20


def test_a_take_of_a_past_ai_turn_does_not_stack_its_script(client):
    """Two turns played, then the first one taken again.

    The take leaves the path just before turn one, so the state it starts from
    is the state turn one started from — nothing, not the twenty that two turns
    had accumulated. Then its own run adds ten.
    """
    _play(client)
    _play(client, "press on")
    assert _gold(client.adv_id) == 20

    first_ai = _rows(client.adv_id, "ai")[0]
    _take(client, first_ai.id)

    assert _gold(client.adv_id) == 10, "rolled back to before that turn, then run once"


def test_a_take_of_a_player_turn_does_not_stack_its_script(client):
    _play(client)
    _play(client, "press on")
    assert _gold(client.adv_id) == 20

    first_player = _rows(client.adv_id, "do")[0]
    _take(client, first_player.id, "> You do something else.")

    assert _gold(client.adv_id) == 10


def test_writing_below_a_passed_take_starts_from_that_take_s_state(client):
    """The `after_id` road, which forks on the way to writing.

    The take being written under produced the state its own turn left behind —
    ten — and the turn played on top of it adds the next ten. The twenty the
    abandoned line reached has nothing to do with this branch.
    """
    _play(client)
    r = client.post(f"/api/adventures/{client.adv_id}/retry")
    assert r.status_code == 200, r.text
    _play(client, "press on")
    assert _gold(client.adv_id) == 20

    discarded = [a for a in _rows(client.adv_id, "ai") if not a.live][0]
    _play(client, "a different way", after_id=discarded.id)

    assert _gold(client.adv_id) == 20, "that take's ten, plus this turn's ten"


def test_the_line_left_behind_keeps_the_state_it_reached(client):
    """Switching back finds the abandoned line's numbers where it left them."""
    _play(client)
    _play(client, "press on")
    first_ai = _rows(client.adv_id, "ai")[0]
    _take(client, first_ai.id)
    assert _gold(client.adv_id) == 10

    branches = client.get(f"/api/adventures/{client.adv_id}/branches").json()
    root = [b for b in branches if b["parent_branch_id"] is None][0]
    r = client.post(f"/api/adventures/{client.adv_id}/branches/{root['id']}/switch")
    assert r.status_code == 200, r.text

    assert _gold(client.adv_id) == 20, "the first telling still has its two turns"