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✅ Execute does not mutate input state

CategoryAbility
StatusPassing
Testtests/test_abilities_complex.py::TestCopyOnWrite::test_execute_does_not_mutate_input_state

All handlers must return new state without mutating input. Copy-on-write is enforced.

Preconditions​

  • Focalor in lane 0, Duban (enemy) in lane 1

  • Original state: Duban has 0 damage

Action​

  • Execute Great Blue Spot
result = execute_ability(state, focalor_p, ability_idx=0, choices={"lane": 1})
duban_in_orig = next(d.damage for d in state.demons if d.unit_id == "001")

Expected Postconditions​

  • result.demons[Duban]: fatally wounded (15 Fixed on 6 HP)

  • state.demons[Duban]: 0 damage (original unchanged)

Assertions​

assert duban_in_orig == 0, "Input state was mutated — copy-on-write violated"
assert not any(d.unit_id == "001" for d in result.demons), (
    "Duban must be removed from result board"
)