FaultInjection

Whether this harness can break and heal the links under the rooms it builds — and, when it cannot, where that is written down.

Two arms rather than a nullable FaultyLoom?, because the two carry different claims and only one of them is a limitation anybody has to justify. null said "no fault injection" in a value that costs nothing to write and that no reader has to defend; the second arm below cannot be constructed without naming an issue. That is the difference between a gap that is declared and a gap that is merely taken — and the whole of #2306, whose four silent returns had never once been exercised because the only subclass is the reference, which takes the first arm.

Modelled on BoltConformanceSuite's DurabilityFixture, with one deliberate difference: there, both arms are correct states a backend may legitimately be in, so both assert behaviour. Here the second arm is a shortfall, so what it asserts is its own accountability (injectorOrDeclaredGap fails a blank URL) and the obligation stays unproven. That is the honest shape — inventing an assertion for a state the harness cannot reach would be the vacuity this fixture exists to remove, one level down.

Inheritors