public IEnumerator InitialRemoved()
    {
        yield return(Cache());

        var done = false;

        Autoya.Persist_CacheHashes(
            AutoyaFilePersistTestsFileDomain,
            "h e o w o r d".Split(' '),// l removed.
            () =>
        {
            done = true;
        },
            (code, reason) =>
        {
            Fail("failed to cache items:" + reason);
        }
            );

        yield return(WaitUntil(
                         () =>
        {
            return done;
        },
                         () => { throw new TimeoutException("timeout."); }
                         ));

        // ここで件数チェックを行う。initialが減ってるはず
        var initialFilePaths = Autoya.Persist_DirectoryNamesInDomain(AutoyaFilePersistTestsFileDomain);
        var expected         = "h e o w o r d".Split(' ').Distinct().ToArray().Length;

        True(initialFilePaths.Length == expected, "not match. " + initialFilePaths.Length + " vs " + expected);
    }
    public IEnumerator ContentAdded()
    {
        yield return(Cache());

        var cacheReference = Autoya.Debug_Persist_HashCountByDomain(
            AutoyaFilePersistTestsFileDomain,
            'l'
            );

        var initialFilePaths = Autoya.Persist_DirectoryNamesInDomain(AutoyaFilePersistTestsFileDomain);

        var done = false;

        Autoya.Persist_CacheHashes(
            AutoyaFilePersistTestsFileDomain,
            "h e ll o w o r l d".Split(' '),// ll, added.
            () =>
        {
            done = true;
        },
            (code, reason) =>
        {
            Fail("failed to cache items:" + reason);
        }
            );

        yield return(WaitUntil(
                         () =>
        {
            return done;
        },
                         () => { throw new TimeoutException("timeout."); }
                         ));

        var newInitialFilePaths = Autoya.Persist_DirectoryNamesInDomain(AutoyaFilePersistTestsFileDomain);

        True(initialFilePaths.Length == newInitialFilePaths.Length, "not match.");

        var targetPath = initialFilePaths.Where(p => p.EndsWith("l")).First();

        var lFilePaths = Directory.GetFiles(targetPath);

        True(lFilePaths.Length == 2, "not match, expect:2, actual:" + lFilePaths.Length);

        cacheReference = Autoya.Debug_Persist_HashCountByDomain(
            AutoyaFilePersistTestsFileDomain,
            'l'
            );
        True(cacheReference == 2, "not match, cacheReference:" + cacheReference);
    }