"""In-process checks: every action ends the episode with the same reward. Run: python -m unittest discover -s tests"""
import sys
import unittest
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from models import NullAction  # noqa: E402
from server.environment import REWARD, NullEnvironment  # noqa: E402


class NullEnvTest(unittest.TestCase):
    def test_reset_is_not_terminal(self):
        obs = NullEnvironment().reset(task_id="null")
        self.assertFalse(obs.done)
        self.assertLess(len(obs.prompt), 200)

    def test_every_action_gives_constant_reward(self):
        for payload in ({"answer": "done"}, {}, {"answer": "x", "tool": "calc", "n": 3}, {"answer": 0}, {"answer": None}):
            env = NullEnvironment()
            env.reset(task_id="null")
            obs = env.step(NullAction.model_validate(payload))
            self.assertTrue(obs.done)
            self.assertEqual(obs.reward, REWARD)

    def test_reward_is_half(self):
        self.assertEqual(REWARD, 0.5)

    def test_unknown_task_rejected(self):
        with self.assertRaises(ValueError):
            NullEnvironment().reset(task_id="other")


if __name__ == "__main__":
    unittest.main()