//      output tensor naming, but it the index is actually an input index)
struct EdgeSpec : public std::pair<string, string> {
  typedef std::pair<string, string> Base;

  // Inherit the set of constructors
  using Base::pair;

  string ToString() const { return strings::StrCat(first, "->", second); }
};

class CApiFunctionTest : public ::testing::Test {
 protected:
  CApiFunctionTest()

// don't want to have a `std::vector<std::string>` at global level, we use a
// static pointer to such a vector: we construct it via `SchemeVector()` below
// and when tests are instantiated we process it using `GetSchemes()`.
static std::vector<std::string>* SchemeVector() {
  static std::vector<std::string>* schemes = new std::vector<std::string>;
  return schemes;
}

  ASSERT_EQ(TF_OK, TF_GetCode(s)) << TF_Message(s);

  // Test TF_Operation*() query functions.
  EXPECT_EQ(string("feed"), string(TF_OperationName(feed)));
  EXPECT_EQ(string("Placeholder"), string(TF_OperationOpType(feed)));
  EXPECT_EQ(string(""), string(TF_OperationDevice(feed)));
  EXPECT_EQ(1, TF_OperationNumOutputs(feed));
  EXPECT_EQ(TF_INT32, TF_OperationOutputType(TF_Output{feed, 0}));

                          remote_device) != device_names.end());
  }

  // Create a variable using `ctx_0`.
  // Replace worker1 using a new worker, and update the contexts.
  // Read the variable using `ctx_1`. This read should succeed.
  //
  // 1. Create a variable on `remote_device`, using `ctx_0`.
  TFE_TensorHandle* handle_0 =
      CreateVariable(ctx_0, 1.2, remote_device, /*variable_name=*/"var");