tests/runtime/test_director_no_overlap.py

# tests/runtime/test_director_no_overlap.py
"""Authored memory must never show two ALIVE agents with overlapping footprints.

Agent movement in the director only checked grid bounds, never collisions with
other agents, so two agents' NxN footprints could overlap in a rendered frame.
This is a physics bug: agents are solid bodies. The predator is exempt
(overlap with a distractor is the kill mechanic).
"""
import pytest

from proteus.game.runtime.multiagent_director import (
    author_predator_chase,
    author_resource_race,
)

_PRED_STARTS = [(10, 30), (14, 38), (18, 24), (12, 46)]
_PRED = (54, 31)
_RES_STARTS = [(8, 52), (20, 10), (40, 50), (55, 20), (30, 30)]
_RES = (54, 12)
_SEEDS = (0, 3, 7)


def _footprints_overlap(ax, ay, asz, bx, by, bsz):
    return ax < bx + bsz and bx < ax + asz and ay < by + bsz and by < ay + asz


def _first_agent_overlap(ck):
    """Return (turn_idx, id_a, id_b) of the first alive agent-agent overlap, or None."""
    for t in ck.memory_turns:
        live = [a for a in t.agents if a.kind == "agent" and a.alive]
        for i in range(len(live)):
            for j in range(i + 1, len(live)):
                a, b = live[i], live[j]
                if _footprints_overlap(
                    a.pos[0], a.pos[1], a.size, b.pos[0], b.pos[1], b.size
                ):
                    return (t.turn_idx, a.id, b.id)
    return None


@pytest.mark.parametrize("seed", _SEEDS)
def test_predator_chase_no_agent_overlap(seed):
    ck = author_predator_chase(
        seed=seed, agent_starts=_PRED_STARTS, predator_start=_PRED
    )
    overlap = _first_agent_overlap(ck)
    assert overlap is None, f"agent overlap at turn {overlap}"


@pytest.mark.parametrize("seed", _SEEDS)
def test_resource_race_no_agent_overlap(seed):
    ck = author_resource_race(seed=seed, agent_starts=_RES_STARTS, resource=_RES)
    overlap = _first_agent_overlap(ck)
    assert overlap is None, f"agent overlap at turn {overlap}"