when:
        def cachedClasspath = transformer.transform(classpath, transform)

        then:
        cachedClasspath.asFiles == [cachedFile]

        and:
        1 * transform.applyConfigurationTo(_) >> { Hasher hasher -> hasher.putInt(123) }
        1 * transform.apply(_, _, _) >> { entry, visitor, data ->
            assert entry.name == "a.class"
            Pair.of(entry.path, visitor)
        }