cache2.Insert("a", 1);
  cache2.Insert("b", 2);
  cache2.Insert("c", 3);
  cache2.Insert("d", 4);
  EXPECT_TRUE(cache2.Lookup("a", &value));
  EXPECT_EQ(value, 1);
  EXPECT_TRUE(cache2.Lookup("b", &value));
  EXPECT_EQ(value, 2);
  EXPECT_TRUE(cache2.Lookup("c", &value));
  EXPECT_EQ(value, 3);
  EXPECT_TRUE(cache2.Lookup("d", &value));
  EXPECT_EQ(value, 4);

  EXPECT_TRUE(TFE_CancellationManagerDeregisterCallback(c_mgr, token1));
  EXPECT_TRUE(TFE_CancellationManagerTryDeregisterCallback(c_mgr, token3));

  TFE_CancellationManagerStartCancel(c_mgr);
  EXPECT_TRUE(TFE_CancellationManagerIsCancelled(c_mgr));
  EXPECT_TRUE(callback2_invoked);
  TFE_DeleteCancellationManager(c_mgr);
}

TEST(CAPI, ExecutorContextDestructionOrder) {
  TF_Status* status = TF_NewStatus();

    } else {
      ASSERT_TRUE(GetNodeDef(oper, &node_def));
      ADD_FAILURE() << "Unexpected Node: " << node_def.DebugString();
    }
  }
  EXPECT_TRUE(found_placeholder);
  EXPECT_TRUE(found_scalar_const);
  EXPECT_TRUE(found_add);
  EXPECT_TRUE(found_neg);

  // Clean up
  TF_DeleteGraph(graph);
  TF_DeleteStatus(s);
}

TEST(CAPI, UpdateEdge) {
  TF_Status* s = TF_NewStatus();

  tf_gcs_filesystem::RamFileBlockCache cache(16, 32, 0, fetcher);
  std::vector<char> out;

  // First read.
  EXPECT_TRUE(cache.ValidateAndUpdateFileSignature(filename, 123));
  TF_EXPECT_OK(ReadCache(&cache, filename, 0, 16, &out));
  EXPECT_EQ(calls, 1);

  // Second read. Hit cache.
  EXPECT_TRUE(cache.ValidateAndUpdateFileSignature(filename, 123));
  TF_EXPECT_OK(ReadCache(&cache, filename, 0, 16, &out));
  EXPECT_EQ(calls, 1);

}

TEST_P(ModularFileSystemTest, TestFilesExistsNoFiles) {
  const std::vector<std::string> filenames = {};
  EXPECT_TRUE(env_->FilesExist(filenames, /*status=*/nullptr));

  std::vector<Status> statuses;
  EXPECT_TRUE(env_->FilesExist(filenames, &statuses));
  EXPECT_TRUE(statuses.empty());
}

TEST_P(ModularFileSystemTest, TestStatEmptyFile) {
  const std::string filepath = GetURIForPath("a_file");

  const string malformed_text_proto(R"(cluster {
  job {
    name: "worker")");
  TF_Buffer* null_result =
      TFE_GetServerDef(malformed_text_proto.c_str(), status);
  EXPECT_NE(TF_GetCode(status), TF_OK);
  EXPECT_TRUE(absl::StrContains(TF_Message(status),
                                "Invalid text proto for ServerDef"));
  EXPECT_EQ(null_result, nullptr);

  // Cleanup
  TF_DeleteBuffer(result);
  TF_DeleteStatus(status);
}

  matmul.reset(MatMulOp(context.get(), hcustom0.get(), hcpu.get()));
  num_retvals = 1;
  executed = false;
  TFE_Execute(matmul.get(), &retval, &num_retvals, status.get());
  EXPECT_TRUE(executed);
  ASSERT_TRUE(TF_GetCode(status.get()) == TF_OK) << TF_Message(status.get());
  TFE_DeleteTensorHandle(retval);

  // Explicit placement still forces the op onto the requested device

    *op = TF_FinishOperation(desc, s_);
    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
    ASSERT_NE(*op, nullptr);
  }

  FunctionDef fdef() {
    tensorflow::FunctionDef fdef;
    EXPECT_TRUE(GetFunctionDef(func_, &fdef));
    return fdef;
  }

  // logging utility
  template <class Container>
  string ToString(const Container& v) {
    std::stringstream ss;
    ss << "{";

  EXPECT_TF_OK(status_);

  TF_FileStatistics stat;
  tf_gcs_filesystem::Stat(filesystem_, dir.c_str(), &stat, status_);
  EXPECT_TF_OK(status_);
  EXPECT_TRUE(stat.is_directory);
}

TEST_F(GCSFilesystemTest, DeleteDir) {
  tf_gcs_filesystem::Init(filesystem_, status_);
  ASSERT_TF_OK(status_);
  const std::string dir = GetURIForPath("DeleteDir");

  TFE_TensorHandle* hdevice =
      TFE_TensorHandleCopyToDevice(hcpu, ctx, kErrorDevice, status.get());
  EXPECT_NE(TF_OK, TF_GetCode(status.get()));
  const char* msg = "NoSuchDevice:0 unknown device";
  EXPECT_TRUE(strstr(TF_Message(status.get()), msg) != nullptr)
      << TF_Message(status.get());
  TF_SetStatus(status.get(), TF_OK, "");
  const char* kCPUDevice = "CPU:0";
  TFE_TensorHandle* hcopy =