TEST_F(NgramKernelTest, TestNoTokens) {
  MakeOp("|", {3}, "L", "R", -1, false);
  // Batch items are:
  // 0:
  // 1: "a"
  AddInputFromArray<tstring>(TensorShape({1}), {"a"});
  AddInputFromArray<int64>(TensorShape({3}), {0, 0, 1});
  TF_ASSERT_OK(RunOpKernel());

  std::vector<tstring> expected_values(
      {"L|L|R", "L|R|R",             // no input in first split
       "L|L|a", "L|a|R", "a|R|R"});  // second split
  std::vector<int64> expected_splits({0, 2, 5});

  assert_string_equal(expected_values, *GetOutput(0));
  assert_int64_equal(expected_splits, *GetOutput(1));
}
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.