}
    }.test();
  }

  @GwtIncompatible // fairly slow (~40s)
  public void testConcatSingletonAndSingletonYieldsDoubleton() {
    new DoubletonIteratorTester() {
      @Override
      protected Iterator<Integer> newTargetIterator() {
        return Iterators.concat(iterateOver(1), iterateOver(2));
      }
    }.test();
  }

  @GwtIncompatible // fairly slow (~40s)

            string(TF_Message(s_)));

  TF_DeleteFunction(grad_func1);
  TF_DeleteFunction(grad_func2);
}

TEST_F(CApiFunctionTest, ImportFunctionDef) {
  /*
   * Using a fairly complex function with output names
   *
   *                  |  |  |
   *                  v  v  /
   *                  add  /
   *                   |  |
   *            +------+  |