EXPECT_PRED2(UnimplementedOrReturnsCode, status, Code::OK);
  if (!status.ok()) GTEST_SKIP() << "GetChildren() not supported: " << status;

  // All entries must show up in the vector.
  // Must contain only the last name in filenames and dirnames.
  const std::vector<std::string> expected_children = {"a_file", "another_file",
                                                      "a_dir", "another_dir"};

              bool expect_failure = false) {
    DefineT(num_opers, opers, ToOutput(inputs), ToOutput(outputs), output_names,
            expect_failure);
  }

  // Caller must delete[] the returned value
  static const char** ToArray(const std::vector<string>& strs) {
    const char** ptr = nullptr;
    if (!strs.empty()) {
      ptr = new const char*[strs.size()];