feat(combat): add direction field to Action for directional maneuvers

tests/test_direction.py

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+"""Tests for the directional ``direction`` field on directional maneuvers.
+
+L2 of the ``llm-policy-contract`` plan: ``Action`` gains a ``direction``
+field that lets a policy steer the three directional maneuvers (reposition,
+drag, bull_rush) instead of relying on the deterministic default direction
+(first free neighbor / beyond the target / away from the attacker).
+
+When ``direction`` is ``None`` the previous deterministic behavior is kept
+bit-identical.
+"""
+
+from __future__ import annotations
+
+from pf1e_simulator.combat import Action, CombatantState, CombatEngine
+from pf1e_simulator.grid import Grid
+from pf1e_simulator.map import MapSpec, TerrainType
+from pf1e_simulator.models import (
+    AbilityScores,
+    ACProfile,
+    AttackSpec,
+    Combatant,
+    DamageComponent,
+    Saves,
+)
+from pf1e_simulator.rng import ScriptedRng, SeededRng
+
+
+def make_combatant(cid: str, *, attack_bonus: int = 2) -> Combatant:
+    attack = AttackSpec(
+        id=f"{cid}-w",
+        name="sword",
+        kind="melee",
+        attack_bonus=attack_bonus,
+        damage=[DamageComponent(formula="1d4", types=["slashing"])],
+    )
+    return Combatant(
+        id=cid,
+        name=cid,
+        level=1,
+        size="Medium",
+        abilities=AbilityScores(
+            str_score=10, dex_score=10, con_score=10,
+            int_score=10, wis_score=10, cha_score=10,
+        ),
+        hp_max=6,
+        ac=ACProfile(total=13, touch=13, flat_footed=13),
+        bab=attack_bonus,
+        initiative_mod=0,
+        speed_land_ft=30,
+        saves=Saves(fort=0, ref=0, will=0),
+        attacks=[attack],
+    )
+
+
+def make_state(combatant: Combatant, side: str, pos: tuple[int, int]) -> CombatantState:
+    return CombatantState(combatant=combatant, side=side, pos=pos, hp=combatant.hp_max)
+
+
+def make_grid() -> Grid:
+    legend = {".": TerrainType(type="floor", move_cost=1)}
+    spec = MapSpec(name="test", terrain=tuple(["." * 8] * 8), legend=legend)
+    return Grid.from_spec(spec)
+
+
+def make_engine(queue: list[int], states: list[CombatantState]) -> CombatEngine:
+    return CombatEngine(ScriptedRng(queue), make_grid(), states)
+
+
+# --- Test 1: reposition with direction -------------------------------------
+
+def test_reposition_direction_right() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "reposition", direction=(0, 1))
+    assert b.pos == (1, 3)
+
+
+def test_reposition_direction_down() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "reposition", direction=(1, 0))
+    assert b.pos == (2, 2)
+
+
+# --- Test 2: drag with direction -------------------------------------------
+
+def test_drag_direction_up() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "drag", direction=(-1, 0))
+    assert b.pos == (0, 2)
+    assert a.pos == (1, 2)
+
+
+# --- Test 3: bull_rush with direction --------------------------------------
+
+def test_bull_rush_direction_left() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (2, 2))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "bull_rush", direction=(0, -1))
+    assert b.pos == (1, 1)
+
+
+# --- Test 4: invalid direction -> no movement -------------------------------
+
+def test_reposition_direction_out_of_bounds_no_move() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (0, 0))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "reposition", direction=(-1, 0))
+    assert b.pos == (0, 0)
+
+
+def test_reposition_direction_occupied_no_move() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    # direction points at the attacker's own cell -> occupied -> no move
+    engine._execute_maneuver(a, b, "reposition", direction=(0, -1))
+    assert b.pos == (1, 2)
+
+
+def test_bull_rush_direction_out_of_bounds_no_move() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (0, 0))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "bull_rush", direction=(-1, 0))
+    assert b.pos == (0, 0)
+
+
+# --- Test 5: direction=None keeps previous behavior -------------------------
+
+def test_reposition_none_uses_first_free_neighbor() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "reposition")
+    # First free neighbor in _NEIGHBOR_OFFSETS order, skipping attacker's cell.
+    assert b.pos == (0, 1)
+
+
+def test_drag_none_uses_beyond_cell() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "drag")
+    # Beyond the target from the attacker: (1, 3).
+    assert b.pos == (1, 3)
+    assert a.pos == (1, 2)
+
+
+def test_bull_rush_none_uses_away_from_attacker() -> None:
+    a_spec = make_combatant("a")
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (2, 2))
+    b = make_state(b_spec, "monsters", (1, 2))
+    engine = make_engine([12], [a, b])
+    engine._execute_maneuver(a, b, "bull_rush")
+    # Away from attacker (up, since target is above): (0, 2).
+    assert b.pos == (0, 2)
+
+
+# --- Test 6: determinism ----------------------------------------------------
+
+def _run_with_direction(direction: tuple[int, int] | None) -> tuple[str, ...]:
+    a_spec = make_combatant("a", attack_bonus=5)
+    b_spec = make_combatant("b")
+    a = make_state(a_spec, "players", (1, 1))
+    b = make_state(b_spec, "monsters", (1, 2))
+
+    def policy(engine: CombatEngine, state: CombatantState) -> tuple[Action, ...]:
+        if state.combatant.id == "a":
+            return (
+                Action(
+                    kind="maneuver", target_id="b", maneuver="reposition",
+                    direction=direction,
+                ),
+            )
+        return (Action(kind="wait"),)
+
+    engine = CombatEngine(SeededRng(42), make_grid(), [a, b], policy=policy)
+    return engine.run().transcript
+
+
+def test_determinism_same_seed_same_transcript() -> None:
+    assert _run_with_direction((0, 1)) == _run_with_direction((0, 1))
+    assert _run_with_direction(None) == _run_with_direction(None)
+
+
+def test_direction_changes_transcript() -> None:
+    assert _run_with_direction((0, 1)) != _run_with_direction(None)