M({{"add1"}, {"add2"}}),
             {{"feed1", "add1_0:0"},
              {"feed2", "add1_0:1"},
              {"add1_0:sum:0", "add2_0:0"},
              {"feed3", "add2_0:1"},
              {"add1_0:sum:0", "add1"},
              {"add2_0:sum:0", "add2"}},
             {});
}

TEST_F(CApiFunctionTest, FromSubsetOfOps) {
  /*
   *                  |  |  |
   *                  v  v  /

  EXPECT_EQ(string(""), string(TF_OperationDevice(add)));
  EXPECT_EQ(1, TF_OperationNumOutputs(add));
  EXPECT_EQ(TF_INT32, TF_OperationOutputType(TF_Output{add, 0}));
  EXPECT_EQ(1, TF_OperationOutputListLength(add, "sum", s));
  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);
  EXPECT_EQ(2, TF_OperationNumInputs(add));
  EXPECT_EQ(2, TF_OperationInputListLength(add, "inputs", s));
  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);

// called after a successful TF_NewWhile() call.
TF_CAPI_EXPORT extern void TF_AbortWhile(const TF_WhileParams* params);

// Adds operations to compute the partial derivatives of sum of `y`s w.r.t `x`s,
// i.e., d(y_1 + y_2 + ...)/dx_1, d(y_1 + y_2 + ...)/dx_2...
//
// `dx` are used as initial gradients (which represent the symbolic partial
// derivatives of some loss function `L` w.r.t. `y`).