when:
        registerWatchableHierarchies([watchableHierarchy])
        then:
        0 * _

        when:
        addSnapshot(snapshotRegularFile(fileOutsideOfWatchableHierarchy))
        addSnapshot(snapshotRegularFile(fileInDirectoryIgnoredForWatching))
        then:
        0 * _
        vfsHasSnapshotsAt(fileOutsideOfWatchableHierarchy)

        then:
        result == 10

        and:
        interaction {
            snapshotRegularFile(file, TestHashCodes.hashCodeFrom(321))
        }
        1 * calculator.calculate(file, true) >> 10
        0 * _
    }

    def snapshotRegularFile(File file, @Nullable HashCode hashCode = TestHashCodes.hashCodeFrom(123)) {

        when:
        registerWatchableHierarchies(watchableHierarchies)
        then:
        0 * _

        when:
        fileInWatchableHierarchies.createFile()
        addSnapshot(snapshotRegularFile(fileInWatchableHierarchies))
        then:
        1 * watcher.startWatching({ equalIgnoringOrder(it, [probeRegistry.getProbeDirectory(file("first"))]) })

        when:
        registerWatchableHierarchies([watchableHierarchy])
        addSnapshot(snapshotRegularFile(watchableContent))
        then:
        vfsHasSnapshotsAt(watchableContent)
        1 * watcher.startWatching({ equalIgnoringOrder(it, [watchableHierarchy]) })
        0 * _

        when:
        addSnapshot(snapshotRegularFile(unwatchableContent))
        then:
        vfsHasSnapshotsAt(unwatchableContent)