}
        };
    testSupplierThreadSafe(memoizer);
  }

  @J2ktIncompatible
  @GwtIncompatible // Thread
  public void testMemoizedSupplierThreadSafe() throws Throwable {
    Function<Supplier<Boolean>, Supplier<Boolean>> memoizer =
        new Function<Supplier<Boolean>, Supplier<Boolean>>() {
          @Override