};

TEST_P(CppGradients, TestIdentityNGrad) {
  // This test is interesting because the current implementation of GradientTape
  // would return [0, 1] whereas we use build_default_zeros_grads=false here
  // so we get back [nullptr, 1].

  AbstractTensorHandlePtr x1;
  {
    AbstractTensorHandle* x1_raw = nullptr;
    status_ = TestScalarTensorHandle<float, TF_FLOAT>(

    }
  }

  TF_RETURN_IF_ERROR(GradientTape::ComputeGradient(
      vspace, target_tensor_ids, source_tensor_ids, sources_that_are_targets,
      output_gradients, result, /*build_default_zeros_grads*/ false));
  return absl::OkStatus();
}

// Helper functions which delegate to `AbstractOperation`, update
// the state of the ForwardOperation and call the tape as appropriate.

// allow us to trace the data dependencies between operations and hence compute
// gradients.
//
// `ZerosLike` is not expected to be called and returns a nullptr. The creation
// of default zeros grads is handled by the `DefaultGradientFunction` registered
// for each op.
// TODO(srbs): We need to define `ZerosLike` here to keep the compiler happy.
// Figure out a way to avoid this.

SyncReplicasOptimizer is removed and SyncReplicasOptimizerV2 renamed to
SyncReplicasOptimizer. * `tf.zeros_initializer()` and `tf.ones_initializer()`
now return a callable that must be called with initializer arguments, in your
code replace `tf.zeros_initializer` with `tf.zeros_initializer()`. *
`SparseTensor.shape` has been renamed to `SparseTensor.dense_shape`. Same for

              {"add2:sum:0", "final_out"}},
             {});
}

TEST_F(CApiFunctionTest, ImportFunctionDef_InvalidProto) {
  // Invalid protobuf data (protos cannot start with 4 bytes of zeros)
  char proto[] = {0x0, 0x0, 0x0, 0x0};
  func_ = TF_FunctionImportFunctionDef(proto, 4, s_);
  EXPECT_TRUE(func_ == nullptr);
  EXPECT_EQ(TF_INVALID_ARGUMENT, TF_GetCode(s_));

  }

  // We may need to allocate zero inputs for trainable dtypes we don't have JVPs
  // for. Make sure they get cleaned up.
  std::vector<Gradient*> new_zeros;
  auto delete_new_zeros = gtl::MakeCleanup([&new_zeros, this] {
    for (Gradient* tensor : new_zeros) {
      this->vspace_.DeleteGradient(tensor);
    }
  });
  std::vector<Gradient*> in_grads;
  in_grads.reserve(input_tensors.size());