ShieldReserveTests.cs covers what Cut 4's InputCapacitorTests.cs cannot: a hit within
the reserve is absorbed and spends charge; a hit beyond it breaks the shield; the
breaking hit is not partially absorbed; a broken shield absorbs nothing (gated on
Broken itself, not merely on the reserve reading empty); a break empties the reserve
regardless of pre-hit charge; a broken shield restores on RestoreDuration and not
RefillDuration; a partial bus grant stretches the refill proportionally.
mutation_tests_shield_reserve.py mutates each rule's own line and confirms the named
test goes red for exactly that reason, plus a no-op control. All 8 (7 rules + control)
verified against the pinned CultLib worktree.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>