You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: checkpoint_create_test.go
    path of file: ./repos/moby/client
    
    the code of the file until where you have to start completion: package client // import "github.com/docker/docker/client"

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"testing"

	"github.com/docker/docker/api/types/checkpoint"
	"github.com/docker/docker/errdefs"
	"gotest.tools/v3/assert"
	is "gotest.tools/v3/assert/cmp"
)

func TestCheckpointCreateError(t *testing.T) {
	client := &Client{
		client: newMockClient(errorMock(http.StatusInternalServerError, "Server error")),
	}
	err := client.CheckpointCreate(context.Background(), "nothing", checkpoint.CreateOptions{
		CheckpointID: "noting",
		Exit:         true,
	})

	assert.Check(t, is.ErrorType(err, errdefs.IsSystem))
}

func TestCheckpoint
    
func TestCheckpointCreate(t *testing.T) {
	expectedContainerID := "container_id"
	expectedCheckpointID := "checkpoint_id"
	expectedURL := "/containers/container_id/checkpoints"

	client := &Client{
		client: newMockClient(func(req *http.Request) (*http.Response, error) {
			if !strings.HasPrefix(req.URL.Path, expectedURL) {
				return nil, fmt.Errorf("Expected URL '%s', got '%s'", expectedURL, req.URL)
			}

			if req.Method != http.MethodPost {
				return nil, fmt.Errorf("expected POST method, got %s", req.Method)
			}

			createOptions := &checkpoint.CreateOptions{}
			if err := json.NewDecoder(req.Body).Decode(createOptions); err != nil {
				return nil, err
			}

			if createOptions.CheckpointID != expectedCheckpointID {
				return nil, fmt.Errorf("expected CheckpointID to be 'checkpoint_id', got %v", createOptions.CheckpointID)
			}

			if !createOptions.Exit {
				return nil, fmt.Errorf("expected Exit to be true")
			}

			return &http.Response{
				StatusCode: http.StatusOK,
				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
			}, nil
		}),
	}

	err := client.CheckpointCreate(context.Background(), expectedContainerID, checkpoint.CreateOptions{
		CheckpointID: expectedCheckpointID,
		Exit:         true,
	})
	if err != nil {
		t.Fatal(err)
	}
}