client: simplify test with mock-responses

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

client/checkpoint_create_test.go

@@ -1,12 +1,10 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -62,11 +60,7 @@ func TestCheckpointCreate(t *testing.T) {
 			if !createOptions.Exit {
 				return nil, errors.New("expected Exit to be true")
 			}
-
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/checkpoint_delete_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -41,10 +39,7 @@ func TestCheckpointDelete(t *testing.T) {
 			if err := assertRequest(req, http.MethodDelete, expectedURL); err != nil {
 				return nil, err
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/checkpoint_list_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -32,18 +29,9 @@ func TestCheckpointList(t *testing.T) {
 			if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 				return nil, err
 			}
-			content, err := json.Marshal([]checkpoint.Summary{
-				{
-					Name: "checkpoint",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []checkpoint.Summary{
+				{Name: "checkpoint"},
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/config_create_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -31,16 +28,9 @@ func TestConfigCreate(t *testing.T) {
 			if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 				return nil, err
 			}
-			b, err := json.Marshal(swarm.ConfigCreateResponse{
+			return mockJSONResponse(http.StatusCreated, nil, swarm.ConfigCreateResponse{
 				ID: "test_config",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusCreated,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/config_inspect_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -68,16 +65,9 @@ func TestConfigInspect(t *testing.T) {
 			if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 				return nil, err
 			}
-			content, err := json.Marshal(swarm.Config{
+			return mockJSONResponse(http.StatusOK, nil, swarm.Config{
 				ID: "config_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/config_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -62,21 +59,10 @@ func TestConfigList(t *testing.T) {
 						return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 					}
 				}
-				content, err := json.Marshal([]swarm.Config{
-					{
-						ID: "config_id1",
-					},
-					{
-						ID: "config_id2",
-					},
-				})
-				if err != nil {
-					return nil, err
-				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader(content)),
-				}, nil
+				return mockJSONResponse(http.StatusOK, nil, []swarm.Config{
+					{ID: "config_id1"},
+					{ID: "config_id2"},
+				})(req)
 			}),
 		)
 		assert.NilError(t, err)

client/config_remove_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -38,10 +36,7 @@ func TestConfigRemove(t *testing.T) {
 			if err := assertRequest(req, http.MethodDelete, expectedURL); err != nil {
 				return nil, err
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/config_update_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -38,10 +36,7 @@ func TestConfigUpdate(t *testing.T) {
 			if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 				return nil, err
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_commit_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -79,16 +76,9 @@ func TestContainerCommit(t *testing.T) {
 			if len(changes) != len(expectedChanges) {
 				return nil, fmt.Errorf("expected container changes size to be '%d', got %d", len(expectedChanges), len(changes))
 			}
-			b, err := json.Marshal(container.CommitResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.CommitResponse{
 				ID: "new_container_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_copy_test.go

@@ -48,12 +48,7 @@ func TestContainerStatPathNotFoundError(t *testing.T) {
 
 func TestContainerStatPathNoHeaderError(t *testing.T) {
 	client, err := NewClientWithOpts(
-		WithMockClient(func(req *http.Request) (*http.Response, error) {
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
-		}),
+		WithMockClient(mockResponse(http.StatusOK, nil, "")),
 	)
 	assert.NilError(t, err)
 
@@ -84,13 +79,10 @@ func TestContainerStatPath(t *testing.T) {
 				return nil, err
 			}
 			base64PathStat := base64.StdEncoding.EncodeToString(content)
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-				Header: http.Header{
-					"X-Docker-Container-Path-Stat": []string{base64PathStat},
-				},
-			}, nil
+			hdr := http.Header{
+				"X-Docker-Container-Path-Stat": []string{base64PathStat},
+			}
+			return mockResponse(http.StatusOK, hdr, "")(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -171,10 +163,7 @@ func TestCopyToContainer(t *testing.T) {
 				return nil, fmt.Errorf("expected content to be 'content', got %s", string(content))
 			}
 
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -226,12 +215,10 @@ func TestCopyFromContainerEmptyResponse(t *testing.T) {
 				return nil, err
 			}
 			base64PathStat := base64.StdEncoding.EncodeToString(content)
-			return &http.Response{
-				StatusCode: http.StatusNoContent,
-				Header: http.Header{
-					"X-Docker-Container-Path-Stat": []string{base64PathStat},
-				},
-			}, nil
+			hdr := http.Header{
+				"X-Docker-Container-Path-Stat": []string{base64PathStat},
+			}
+			return mockResponse(http.StatusNoContent, hdr, "")(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -242,12 +229,7 @@ func TestCopyFromContainerEmptyResponse(t *testing.T) {
 
 func TestCopyFromContainerNoHeaderError(t *testing.T) {
 	client, err := NewClientWithOpts(
-		WithMockClient(func(req *http.Request) (*http.Response, error) {
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
-		}),
+		WithMockClient(mockResponse(http.StatusOK, nil, "")),
 	)
 	assert.NilError(t, err)
 
@@ -279,14 +261,10 @@ func TestCopyFromContainer(t *testing.T) {
 				return nil, err
 			}
 			base64PathStat := base64.StdEncoding.EncodeToString(headercontent)
-
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("content"))),
-				Header: http.Header{
-					"X-Docker-Container-Path-Stat": []string{base64PathStat},
-				},
-			}, nil
+			hdr := http.Header{
+				"X-Docker-Container-Path-Stat": []string{base64PathStat},
+			}
+			return mockResponse(http.StatusOK, hdr, "content")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_create_test.go

@@ -1,12 +1,10 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -60,16 +58,9 @@ func TestContainerCreateWithName(t *testing.T) {
 			if name != "container_name" {
 				return nil, fmt.Errorf("container name not set in URL query properly. Expected `container_name`, got %s", name)
 			}
-			b, err := json.Marshal(container.CreateResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.CreateResponse{
 				ID: "container_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -89,16 +80,9 @@ func TestContainerCreateAutoRemove(t *testing.T) {
 			if !config.HostConfig.AutoRemove {
 				return nil, errors.New("expected AutoRemove to be enabled")
 			}
-			b, err := json.Marshal(container.CreateResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.CreateResponse{
 				ID: "container_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -151,16 +135,9 @@ func TestContainerCreateCapabilities(t *testing.T) {
 			assert.Check(t, is.DeepEqual(config.HostConfig.CapAdd, expectedCaps))
 			assert.Check(t, is.DeepEqual(config.HostConfig.CapDrop, expectedCaps))
 
-			b, err := json.Marshal(container.CreateResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.CreateResponse{
 				ID: "container_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_diff_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -55,14 +52,7 @@ func TestContainerDiff(t *testing.T) {
 			if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 				return nil, err
 			}
-			b, err := json.Marshal(expected)
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, expected)(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_exec_test.go

@@ -1,11 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -63,16 +61,9 @@ func TestExecCreate(t *testing.T) {
 			if execConfig.User != "user" {
 				return nil, fmt.Errorf("expected an execConfig with User == 'user', got %v", execConfig)
 			}
-			b, err := json.Marshal(container.ExecCreateResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.ExecCreateResponse{
 				ID: "exec_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -111,11 +102,7 @@ func TestExecStart(t *testing.T) {
 			if request.Tty || !request.Detach {
 				return nil, fmt.Errorf("expected ExecStartOptions{Detach:true,Tty:false}, got %v", request)
 			}
-
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)
@@ -144,17 +131,10 @@ func TestExecInspect(t *testing.T) {
 			if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 				return nil, err
 			}
-			b, err := json.Marshal(container.ExecInspectResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.ExecInspectResponse{
 				ID:          "exec_id",
 				ContainerID: "container_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_export_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"io"
 	"net/http"
@@ -37,10 +36,7 @@ func TestContainerExport(t *testing.T) {
 			if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 				return nil, err
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("response"))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "response")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_inspect_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -75,18 +72,11 @@ func TestContainerInspect(t *testing.T) {
 			if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 				return nil, err
 			}
-			content, err := json.Marshal(container.InspectResponse{
+			return mockJSONResponse(http.StatusOK, nil, container.InspectResponse{
 				ID:    "container_id",
 				Image: "image",
 				Name:  "name",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_kill_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -42,10 +40,7 @@ func TestContainerKill(t *testing.T) {
 			if signal != "SIGKILL" {
 				return nil, fmt.Errorf("signal not set in URL query properly. Expected 'SIGKILL', got %s", signal)
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -60,23 +57,10 @@ func TestContainerList(t *testing.T) {
 			if fltrs != expectedFilters {
 				return nil, fmt.Errorf("expected filters incoherent '%v' with actual filters %v", expectedFilters, fltrs)
 			}
-
-			b, err := json.Marshal([]container.Summary{
-				{
-					ID: "container_id1",
-				},
-				{
-					ID: "container_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []container.Summary{
+				{ID: "container_id1"},
+				{ID: "container_id2"},
+			})(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_logs_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -140,10 +139,7 @@ func TestContainerLogs(t *testing.T) {
 						return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 					}
 				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte("response"))),
-				}, nil
+				return mockResponse(http.StatusOK, nil, "response")(req)
 			}),
 		)
 		assert.NilError(t, err)

client/container_pause_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -29,10 +27,7 @@ func TestContainerPause(t *testing.T) {
 			if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 				return nil, err
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}),
 	)
 	assert.NilError(t, err)

client/container_prune_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -85,17 +82,10 @@ func TestContainersPrune(t *testing.T) {
 				actual := query.Get(key)
 				assert.Check(t, is.Equal(expected, actual))
 			}
-			content, err := json.Marshal(container.PruneReport{
+			return mockJSONResponse(http.StatusOK, nil, container.PruneReport{
 				ContainersDeleted: []string{"container_id1", "container_id2"},
 				SpaceReclaimed:    9999,
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/container_remove_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -55,10 +53,7 @@ func TestContainerRemove(t *testing.T) {
 		if link != "" {
 			return nil, fmt.Errorf("link should have not be present in query, go %s", link)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/container_rename_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -38,10 +36,7 @@ func TestContainerRename(t *testing.T) {
 		if name != "newName" {
 			return nil, fmt.Errorf("name not set in URL query properly. Expected 'newName', got %s", name)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/container_resize_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"math"
 	"net/http"
 	"testing"
@@ -127,9 +125,6 @@ func resizeTransport(t *testing.T, expectedURL, expectedHeight, expectedWidth st
 		query := req.URL.Query()
 		assert.Check(t, is.Equal(query.Get("h"), expectedHeight))
 		assert.Check(t, is.Equal(query.Get("w"), expectedWidth))
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}
 }

client/container_restart_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -54,10 +52,7 @@ func TestContainerRestart(t *testing.T) {
 		if t != "100" {
 			return nil, fmt.Errorf("t (timeout) not set in URL query properly. Expected '100', got %s", t)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 	timeout := 100

client/container_start_test.go

@@ -1,11 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -47,11 +45,7 @@ func TestContainerStart(t *testing.T) {
 		if checkpoint != "checkpoint_id" {
 			return nil, fmt.Errorf("checkpoint not set in URL query properly. Expected 'checkpoint_id', got %s", checkpoint)
 		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/container_stats_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -53,11 +52,7 @@ func TestContainerStats(t *testing.T) {
 			if stream != tc.expectedStream {
 				return nil, fmt.Errorf("stream not set in URL query properly. Expected '%s', got %s", tc.expectedStream, stream)
 			}
-
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("response"))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "response")(req)
 		}))
 		assert.NilError(t, err)
 		resp, err := client.ContainerStats(context.Background(), "container_id", tc.stream)

client/container_stop_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -54,10 +52,7 @@ func TestContainerStop(t *testing.T) {
 		if t != "100" {
 			return nil, fmt.Errorf("t (timeout) not set in URL query properly. Expected '100', got %s", t)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 	timeout := 100

client/container_top_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -47,22 +44,13 @@ func TestContainerTop(t *testing.T) {
 		if args != "arg1 arg2" {
 			return nil, fmt.Errorf("args not set in URL query properly. Expected 'arg1 arg2', got %v", args)
 		}
-
-		b, err := json.Marshal(container.TopResponse{
+		return mockJSONResponse(http.StatusOK, nil, container.TopResponse{
 			Processes: [][]string{
 				{"p1", "p2"},
 				{"p3"},
 			},
 			Titles: []string{"title1", "title2"},
-		})
-		if err != nil {
-			return nil, err
-		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/container_unpause_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -33,10 +31,7 @@ func TestContainerUnpause(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 	err = client.ContainerUnpause(context.Background(), "container_id")

client/container_update_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -36,16 +33,7 @@ func TestContainerUpdate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-
-		b, err := json.Marshal(container.UpdateResponse{})
-		if err != nil {
-			return nil, err
-		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		return mockJSONResponse(http.StatusOK, nil, container.UpdateResponse{})(req)
 	}))
 	assert.NilError(t, err)
 

client/container_wait_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
 	"io"
 	"log"
@@ -55,16 +53,9 @@ func TestContainerWait(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		b, err := json.Marshal(container.WaitResponse{
+		return mockJSONResponse(http.StatusOK, nil, container.WaitResponse{
 			StatusCode: 15,
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 
@@ -87,10 +78,7 @@ func TestContainerWaitProxyInterrupt(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(strings.NewReader(expErr)),
-		}, nil
+		return mockResponse(http.StatusOK, nil, expErr)(req)
 	}))
 	assert.NilError(t, err)
 
@@ -110,10 +98,7 @@ func TestContainerWaitProxyInterruptLong(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(strings.NewReader(msg)),
-		}, nil
+		return mockResponse(http.StatusOK, nil, msg)(req)
 	}))
 	assert.NilError(t, err)
 

client/image_build_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -186,10 +185,7 @@ func TestImageBuild(t *testing.T) {
 				}
 			}
 
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "body")(req)
 		}))
 		assert.NilError(t, err)
 		buildResponse, err := client.ImageBuild(context.Background(), nil, buildCase.buildOptions)

client/image_create_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -50,10 +49,7 @@ func TestImageCreate(t *testing.T) {
 			return nil, fmt.Errorf("tag not set in URL query properly. Expected '%s', got %s", expectedTag, tag)
 		}
 
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/image_history_test.go

@@ -2,9 +2,7 @@ package client
 
 import (
 	"context"
-	"io"
 	"net/http"
-	"strings"
 	"testing"
 
 	cerrdefs "github.com/containerd/errdefs"
@@ -30,10 +28,7 @@ func TestImageHistory(t *testing.T) {
 	client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
 		assert.Check(t, assertRequest(req, http.MethodGet, expectedURL))
 		assert.Check(t, is.Equal(req.URL.Query().Get("platform"), expectedPlatform))
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(strings.NewReader(historyResponse)),
-		}, nil
+		return mockResponse(http.StatusOK, nil, historyResponse)(req)
 	}))
 	assert.NilError(t, err)
 	expected := ImageHistoryResult{

client/image_import_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"io"
 	"net/http"
@@ -71,10 +70,7 @@ func TestImageImport(t *testing.T) {
 				assert.Check(t, assertRequest(req, http.MethodPost, expectedURL))
 				query := req.URL.Query()
 				assert.Check(t, is.DeepEqual(query, tc.expectedQueryParams))
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte(expectedOutput))),
-				}, nil
+				return mockResponse(http.StatusOK, nil, expectedOutput)(req)
 			}))
 			assert.NilError(t, err)
 			result, err := client.ImageImport(context.Background(), ImageImportSource{

client/image_inspect_test.go

@@ -1,12 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -49,17 +46,10 @@ func TestImageInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(image.InspectResponse{
+		return mockJSONResponse(http.StatusOK, nil, image.InspectResponse{
 			ID:       "image_id",
 			RepoTags: expectedTags,
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 
@@ -90,18 +80,11 @@ func TestImageInspectWithPlatform(t *testing.T) {
 			return nil, fmt.Errorf("Expected platform '%s', got '%s'", expectedPlatform, platform)
 		}
 
-		content, err := json.Marshal(image.InspectResponse{
+		return mockJSONResponse(http.StatusOK, nil, image.InspectResponse{
 			ID:           "image_id",
 			Architecture: "arm64",
 			Os:           "linux",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/image_list_test.go

@@ -1,14 +1,10 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"net/url"
-	"strings"
 	"testing"
 
 	cerrdefs "github.com/containerd/errdefs"
@@ -88,21 +84,10 @@ func TestImageList(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			content, err := json.Marshal([]image.Summary{
-				{
-					ID: "image_id2",
-				},
-				{
-					ID: "image_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []image.Summary{
+				{ID: "image_id2"},
+				{ID: "image_id2"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 
@@ -131,10 +116,7 @@ func TestImageListWithSharedSize(t *testing.T) {
 			var query url.Values
 			client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
 				query = req.URL.Query()
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(strings.NewReader("[]")),
-				}, nil
+				return mockResponse(http.StatusOK, nil, "[]")(req)
 			}), WithVersion(tc.version))
 			assert.NilError(t, err)
 			_, err = client.ImageList(context.Background(), tc.options)

client/image_load_test.go

@@ -85,11 +85,9 @@ func TestImageLoad(t *testing.T) {
 				assert.Check(t, assertRequest(req, http.MethodPost, expectedURL))
 				assert.Check(t, is.Equal(req.Header.Get("Content-Type"), expectedContentType))
 				assert.Check(t, is.DeepEqual(req.URL.Query(), tc.expectedQueryParams))
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte(expectedOutput))),
-					Header:     http.Header{"Content-Type": []string{tc.responseContentType}},
-				}, nil
+
+				hdr := http.Header{"Content-Type": []string{tc.responseContentType}}
+				return mockResponse(http.StatusOK, hdr, expectedOutput)(req)
 			}))
 			assert.NilError(t, err)
 

client/image_prune_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -75,24 +72,14 @@ func TestImagesPrune(t *testing.T) {
 				actual := query.Get(key)
 				assert.Check(t, is.Equal(expected, actual))
 			}
-			content, err := json.Marshal(image.PruneReport{
+
+			return mockJSONResponse(http.StatusOK, nil, image.PruneReport{
 				ImagesDeleted: []image.DeleteResponse{
-					{
-						Deleted: "image_id1",
-					},
-					{
-						Deleted: "image_id2",
-					},
+					{Deleted: "image_id1"},
+					{Deleted: "image_id2"},
 				},
 				SpaceReclaimed: 9999,
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/image_pull_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -72,10 +71,7 @@ func TestImagePullWithPrivilegedFuncNoError(t *testing.T) {
 		}
 		auth := req.Header.Get(registry.AuthHeader)
 		if auth == invalidAuth {
-			return &http.Response{
-				StatusCode: http.StatusUnauthorized,
-				Body:       io.NopCloser(bytes.NewReader([]byte("Invalid credentials"))),
-			}, nil
+			return mockResponse(http.StatusUnauthorized, nil, "Invalid credentials")(req)
 		}
 		if auth != validAuth {
 			return nil, fmt.Errorf("invalid auth header: expected %s, got %s", "IAmValid", auth)
@@ -89,10 +85,7 @@ func TestImagePullWithPrivilegedFuncNoError(t *testing.T) {
 		if tag != "latest" {
 			return nil, fmt.Errorf("tag not set in URL query properly. Expected '%s', got %s", "latest", tag)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("hello world"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "hello world")(req)
 	}))
 	assert.NilError(t, err)
 	resp, err := client.ImagePull(context.Background(), "myimage", ImagePullOptions{
@@ -181,10 +174,7 @@ func TestImagePullWithoutErrors(t *testing.T) {
 				if tag != pullCase.expectedTag {
 					return nil, fmt.Errorf("tag not set in URL query properly. Expected '%s', got %s", pullCase.expectedTag, tag)
 				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte(expectedOutput))),
-				}, nil
+				return mockResponse(http.StatusOK, nil, expectedOutput)(req)
 			}))
 			assert.NilError(t, err)
 			resp, err := client.ImagePull(context.Background(), pullCase.reference, ImagePullOptions{

client/image_push_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -76,10 +75,7 @@ func TestImagePushWithPrivilegedFuncNoError(t *testing.T) {
 		}
 		auth := req.Header.Get(registry.AuthHeader)
 		if auth == invalidAuth {
-			return &http.Response{
-				StatusCode: http.StatusUnauthorized,
-				Body:       io.NopCloser(bytes.NewReader([]byte("Invalid credentials"))),
-			}, nil
+			return mockResponse(http.StatusUnauthorized, nil, "Invalid credentials")(req)
 		}
 		if auth != validAuth {
 			return nil, fmt.Errorf("invalid auth header: expected %s, got %s", "IAmValid", auth)
@@ -89,10 +85,7 @@ func TestImagePushWithPrivilegedFuncNoError(t *testing.T) {
 		if tag != "tag" {
 			return nil, fmt.Errorf("tag not set in URL query properly. Expected '%s', got %s", "tag", tag)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("hello world"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "hello world")(req)
 	}))
 	assert.NilError(t, err)
 	resp, err := client.ImagePush(context.Background(), "myname/myimage:tag", ImagePushOptions{
@@ -178,10 +171,7 @@ func TestImagePushWithoutErrors(t *testing.T) {
 				if tag != tc.expectedTag {
 					return nil, fmt.Errorf("tag not set in URL query properly. Expected '%s', got %s", tc.expectedTag, tag)
 				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte(expectedOutput))),
-				}, nil
+				return mockResponse(http.StatusOK, nil, expectedOutput)(req)
 			}))
 			assert.NilError(t, err)
 			resp, err := client.ImagePush(context.Background(), tc.reference, ImagePushOptions{

client/image_remove_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -79,22 +76,10 @@ func TestImageRemove(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			b, err := json.Marshal([]image.DeleteResponse{
-				{
-					Untagged: "image_id1",
-				},
-				{
-					Deleted: "image_id",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []image.DeleteResponse{
+				{Untagged: "image_id1"},
+				{Deleted: "image_id"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/image_save_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"io"
 	"net/http"
@@ -67,10 +66,7 @@ func TestImageSave(t *testing.T) {
 			client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
 				assert.Check(t, assertRequest(req, http.MethodGet, expectedURL))
 				assert.Check(t, is.DeepEqual(req.URL.Query(), tc.expectedQueryParams))
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte(expectedOutput))),
-				}, nil
+				return mockResponse(http.StatusOK, nil, expectedOutput)(req)
 			}))
 			assert.NilError(t, err)
 			resp, err := client.ImageSave(context.Background(), []string{"image_id1", "image_id2"}, tc.options...)

client/image_search_test.go

@@ -1,12 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -62,10 +59,7 @@ func TestImageSearchWithPrivilegedFuncNoError(t *testing.T) {
 		}
 		auth := req.Header.Get(registry.AuthHeader)
 		if auth == "NotValid" {
-			return &http.Response{
-				StatusCode: http.StatusUnauthorized,
-				Body:       io.NopCloser(bytes.NewReader([]byte("Invalid credentials"))),
-			}, nil
+			return mockResponse(http.StatusUnauthorized, nil, "Invalid credentials")(req)
 		}
 		if auth != "IAmValid" {
 			return nil, fmt.Errorf("invalid auth header: expected 'IAmValid', got %s", auth)
@@ -75,18 +69,9 @@ func TestImageSearchWithPrivilegedFuncNoError(t *testing.T) {
 		if term != "some-image" {
 			return nil, fmt.Errorf("term not set in URL query properly. Expected 'some-image', got %s", term)
 		}
-		content, err := json.Marshal([]registry.SearchResult{
-			{
-				Name: "anything",
-			},
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		return mockJSONResponse(http.StatusOK, nil, []registry.SearchResult{
+			{Name: "anything"},
+		})(req)
 	}))
 	assert.NilError(t, err)
 	privilegeFunc := func(_ context.Context) (string, error) {
@@ -117,18 +102,9 @@ func TestImageSearchWithoutErrors(t *testing.T) {
 		if fltrs != expectedFilters {
 			return nil, fmt.Errorf("filters not set in URL query properly. Expected '%s', got %s", expectedFilters, fltrs)
 		}
-		content, err := json.Marshal([]registry.SearchResult{
-			{
-				Name: "anything",
-			},
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		return mockJSONResponse(http.StatusOK, nil, []registry.SearchResult{
+			{Name: "anything"},
+		})(req)
 	}))
 	assert.NilError(t, err)
 	results, err := client.ImageSearch(context.Background(), "some-image", ImageSearchOptions{

client/image_tag_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"math/rand"
 	"net/http"
 	"testing"
@@ -88,7 +86,7 @@ func generateRandomAlphaOnlyString(n int) string {
 }
 
 func TestImageTagHexSource(t *testing.T) {
-	client, err := NewClientWithOpts(WithMockClient(errorMock(http.StatusOK, "OK")))
+	client, err := NewClientWithOpts(WithMockClient(mockResponse(http.StatusOK, nil, "OK")))
 	assert.NilError(t, err)
 
 	_, err = client.ImageTag(context.Background(), ImageTagOptions{Source: "0d409d33b27e47423b049f7f863faa08655a8c901749c2b25b93ca67d01a470d", Target: "repo:tag"})
@@ -163,10 +161,7 @@ func TestImageTag(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}))
 		assert.NilError(t, err)
 		_, err = client.ImageTag(context.Background(), ImageTagOptions{Source: "image_id", Target: tagCase.reference})

client/network_connect_test.go

@@ -1,11 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -53,10 +51,7 @@ func TestNetworkConnectEmptyNilEndpointSettings(t *testing.T) {
 			return nil, fmt.Errorf("expected connect.EndpointConfig to be nil, got %v", connect.EndpointConfig)
 		}
 
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 
@@ -89,10 +84,7 @@ func TestNetworkConnect(t *testing.T) {
 			return nil, fmt.Errorf("expected 'NetworkID', got %s", connect.EndpointConfig.NetworkID)
 		}
 
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/network_create_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -41,18 +38,10 @@ func TestNetworkCreate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-
-		content, err := json.Marshal(network.CreateResponse{
+		return mockJSONResponse(http.StatusOK, nil, network.CreateResponse{
 			ID:      "network_id",
 			Warning: "warning",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/network_disconnect_test.go

@@ -1,11 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -52,10 +50,7 @@ func TestNetworkDisconnect(t *testing.T) {
 			return nil, fmt.Errorf("expected Force to be true, got %v", disconnect.Force)
 		}
 
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/network_inspect_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -36,31 +33,20 @@ func TestNetworkInspect(t *testing.T) {
 		if strings.Contains(req.URL.RawQuery, "scope=global") {
 			return errorMock(http.StatusNotFound, "Error: No such network: network_id")(req)
 		}
-		var (
-			content []byte
-			err     error
-		)
+		var resp network.Inspect
 		if strings.Contains(req.URL.RawQuery, "verbose=true") {
-			s := map[string]network.ServiceInfo{
-				"web": {},
-			}
-			content, err = json.Marshal(network.Inspect{
-				Network:  network.Network{Name: "mynetwork"},
-				Services: s,
-			})
-		} else {
-			content, err = json.Marshal(network.Inspect{
+			resp = network.Inspect{
 				Network: network.Network{Name: "mynetwork"},
-			})
+				Services: map[string]network.ServiceInfo{
+					"web": {},
+				},
+			}
+		} else {
+			resp = network.Inspect{
+				Network: network.Network{Name: "mynetwork"},
+			}
 		}
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			Header:     http.Header{"Content-Type": []string{"application/json"}},
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		return mockJSONResponse(http.StatusOK, nil, resp)(req)
 	}))
 	assert.NilError(t, err)
 

client/network_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -66,21 +63,14 @@ func TestNetworkList(t *testing.T) {
 			if actualFilters != listCase.expectedFilters {
 				return nil, fmt.Errorf("filters not set in URL query properly. Expected '%s', got %s", listCase.expectedFilters, actualFilters)
 			}
-			content, err := json.Marshal([]network.Summary{
+			return mockJSONResponse(http.StatusOK, nil, []network.Summary{
 				{
 					Network: network.Network{
 						Name:   "network",
 						Driver: "bridge",
 					},
 				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/network_prune_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -78,16 +75,9 @@ func TestNetworksPrune(t *testing.T) {
 					actual := query.Get(key)
 					assert.Check(t, is.Equal(expected, actual))
 				}
-				content, err := json.Marshal(network.PruneReport{
+				return mockJSONResponse(http.StatusOK, nil, network.PruneReport{
 					NetworksDeleted: []string{"network_id1", "network_id2"},
-				})
-				if err != nil {
-					return nil, err
-				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader(content)),
-				}, nil
+				})(req)
 			}),
 		)
 		assert.NilError(t, err)

client/network_remove_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestNetworkRemove(t *testing.T) {
 		if err := assertRequest(req, http.MethodDelete, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/node_inspect_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -51,16 +48,9 @@ func TestNodeInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(swarm.Node{
+		return mockJSONResponse(http.StatusOK, nil, swarm.Node{
 			ID: "node_id",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/node_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -58,21 +55,10 @@ func TestNodeList(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			content, err := json.Marshal([]swarm.Node{
-				{
-					ID: "node_id1",
-				},
-				{
-					ID: "node_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []swarm.Node{
+				{ID: "node_id1"},
+				{ID: "node_id2"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/node_remove_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -55,10 +53,7 @@ func TestNodeRemove(t *testing.T) {
 				return nil, fmt.Errorf("force not set in URL query properly. expected '%s', got %s", removeCase.expectedForce, force)
 			}
 
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "body")(req)
 		}))
 		assert.NilError(t, err)
 

client/node_update_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -45,10 +43,7 @@ func TestNodeUpdate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/ping_test.go

@@ -3,7 +3,6 @@ package client
 import (
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"slices"
 	"strings"
@@ -20,15 +19,14 @@ import (
 func TestPingFail(t *testing.T) {
 	var withHeader bool
 	client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
-		resp := &http.Response{StatusCode: http.StatusInternalServerError}
+		var hdr http.Header
 		if withHeader {
-			resp.Header = http.Header{}
-			resp.Header.Set("Api-Version", "awesome")
-			resp.Header.Set("Docker-Experimental", "true")
-			resp.Header.Set("Swarm", "inactive")
+			hdr = http.Header{}
+			hdr.Set("Api-Version", "awesome")
+			hdr.Set("Docker-Experimental", "true")
+			hdr.Set("Swarm", "inactive")
 		}
-		resp.Body = io.NopCloser(strings.NewReader("some error with the server"))
-		return resp, nil
+		return mockResponse(http.StatusInternalServerError, hdr, "some error with the server")(req)
 	}))
 	assert.NilError(t, err)
 
@@ -67,13 +65,11 @@ func TestPingWithError(t *testing.T) {
 // details on success.
 func TestPingSuccess(t *testing.T) {
 	client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
-		resp := &http.Response{StatusCode: http.StatusOK}
-		resp.Header = http.Header{}
-		resp.Header.Set("Api-Version", "awesome")
-		resp.Header.Set("Docker-Experimental", "true")
-		resp.Header.Set("Swarm", "active/manager")
-		resp.Body = io.NopCloser(strings.NewReader("OK"))
-		return resp, nil
+		hdr := http.Header{}
+		hdr.Set("Api-Version", "awesome")
+		hdr.Set("Docker-Experimental", "true")
+		hdr.Set("Swarm", "active/manager")
+		return mockResponse(http.StatusOK, hdr, "OK")(req)
 	}))
 	assert.NilError(t, err)
 	ping, err := client.Ping(t.Context(), PingOptions{})

client/plugin_disable_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestPluginDisable(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/plugin_enable_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestPluginEnable(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/plugin_inspect_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -42,16 +39,9 @@ func TestPluginInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(plugin.Plugin{
+		return mockJSONResponse(http.StatusOK, nil, plugin.Plugin{
 			ID: "plugin_id",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/plugin_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -67,21 +64,10 @@ func TestPluginList(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			content, err := json.Marshal([]*plugin.Plugin{
-				{
-					ID: "plugin_id1",
-				},
-				{
-					ID: "plugin_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []*plugin.Plugin{
+				{ID: "plugin_id1"},
+				{ID: "plugin_id2"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/plugin_push_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -41,10 +39,7 @@ func TestPluginPush(t *testing.T) {
 		if auth != "authtoken" {
 			return nil, fmt.Errorf("invalid auth header: expected 'authtoken', got %s", auth)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/plugin_remove_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestPluginRemove(t *testing.T) {
 		if err := assertRequest(req, http.MethodDelete, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/plugin_set_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestPluginSet(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/request_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -61,10 +60,7 @@ func TestSetHostHeader(t *testing.T) {
 				if req.URL.Host != tc.expectedURLHost {
 					return nil, fmt.Errorf("expected URL host %q, got %q", tc.expectedURLHost, req.URL.Host)
 				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-				}, nil
+				return mockResponse(http.StatusOK, nil, "")(req)
 			}), WithHost(tc.host))
 			assert.NilError(t, err)
 
@@ -200,11 +196,7 @@ func TestResponseErrors(t *testing.T) {
 	for _, tc := range tests {
 		t.Run(tc.doc, func(t *testing.T) {
 			client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
-				return &http.Response{
-					StatusCode: http.StatusBadRequest,
-					Header:     http.Header{"Content-Type": []string{tc.contentType}},
-					Body:       io.NopCloser(bytes.NewReader([]byte(tc.response))),
-				}, nil
+				return mockResponse(http.StatusBadRequest, http.Header{"Content-Type": []string{tc.contentType}}, tc.response)(req)
 			}))
 			if tc.apiVersion != "" {
 				client, err = NewClientWithOpts(WithHTTPClient(client.client), WithVersion(tc.apiVersion))

client/secret_create_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -27,16 +24,9 @@ func TestSecretCreate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		b, err := json.Marshal(swarm.SecretCreateResponse{
+		return mockJSONResponse(http.StatusCreated, nil, swarm.SecretCreateResponse{
 			ID: "test_secret",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusCreated,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/secret_inspect_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -51,16 +48,9 @@ func TestSecretInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(swarm.Secret{
+		return mockJSONResponse(http.StatusOK, nil, swarm.Secret{
 			ID: "secret_id",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/secret_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -57,21 +54,11 @@ func TestSecretList(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			content, err := json.Marshal([]swarm.Secret{
-				{
-					ID: "secret_id1",
-				},
-				{
-					ID: "secret_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+
+			return mockJSONResponse(http.StatusOK, nil, []swarm.Secret{
+				{ID: "secret_id1"},
+				{ID: "secret_id2"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/secret_remove_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestSecretRemove(t *testing.T) {
 		if err := assertRequest(req, http.MethodDelete, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/secret_update_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -35,10 +33,7 @@ func TestSecretUpdate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/service_create_test.go

@@ -1,11 +1,9 @@
 package client
 
 import (
-	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -44,16 +42,9 @@ func TestServiceCreate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		b, err := json.Marshal(swarm.ServiceCreateResponse{
+		return mockJSONResponse(http.StatusOK, nil, swarm.ServiceCreateResponse{
 			ID: "service_id",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 
@@ -77,18 +68,11 @@ func TestServiceCreateCompatiblePlatforms(t *testing.T) {
 			assert.Check(t, is.Len(serviceSpec.TaskTemplate.Placement.Platforms, 1))
 
 			p := serviceSpec.TaskTemplate.Placement.Platforms[0]
-			b, err := json.Marshal(swarm.ServiceCreateResponse{
+			return mockJSONResponse(http.StatusOK, nil, swarm.ServiceCreateResponse{
 				ID: "service_" + p.OS + "_" + p.Architecture,
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		} else if strings.HasPrefix(req.URL.Path, defaultAPIPath+"/distribution/") {
-			b, err := json.Marshal(registrytypes.DistributionInspect{
+			return mockJSONResponse(http.StatusOK, nil, registrytypes.DistributionInspect{
 				Descriptor: ocispec.Descriptor{
 					Digest: "sha256:c0537ff6a5218ef531ece93d4984efc99bbf3f7497c0a7726c88e2bb7584dc96",
 				},
@@ -98,14 +82,7 @@ func TestServiceCreateCompatiblePlatforms(t *testing.T) {
 						OS:           "linux",
 					},
 				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		} else {
 			return nil, fmt.Errorf("unexpected URL '%s'", req.URL.Path)
 		}
@@ -156,33 +133,19 @@ func TestServiceCreateDigestPinning(t *testing.T) {
 			}
 			serviceCreateImage = service.TaskTemplate.ContainerSpec.Image
 
-			b, err := json.Marshal(swarm.ServiceCreateResponse{
+			return mockJSONResponse(http.StatusOK, nil, swarm.ServiceCreateResponse{
 				ID: "service_id",
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		} else if strings.HasPrefix(req.URL.Path, defaultAPIPath+"/distribution/cannotresolve") {
 			// unresolvable image
 			return nil, errors.New("cannot resolve image")
 		} else if strings.HasPrefix(req.URL.Path, defaultAPIPath+"/distribution/") {
 			// resolvable images
-			b, err := json.Marshal(registrytypes.DistributionInspect{
+			return mockJSONResponse(http.StatusOK, nil, registrytypes.DistributionInspect{
 				Descriptor: ocispec.Descriptor{
 					Digest: digest.Digest(dgst),
 				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(b)),
-			}, nil
+			})(req)
 		}
 		return nil, fmt.Errorf("unexpected URL '%s'", req.URL.Path)
 	}))

client/service_inspect_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -51,16 +48,9 @@ func TestServiceInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(swarm.Service{
+		return mockJSONResponse(http.StatusOK, nil, swarm.Service{
 			ID: "service_id",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/service_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -57,21 +54,11 @@ func TestServiceList(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			content, err := json.Marshal([]swarm.Service{
-				{
-					ID: "service_id1",
-				},
-				{
-					ID: "service_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+
+			return mockJSONResponse(http.StatusOK, nil, []swarm.Service{
+				{ID: "service_id1"},
+				{ID: "service_id2"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/service_logs_test.go

@@ -1,7 +1,6 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -105,10 +104,7 @@ func TestServiceLogs(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("response"))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "response")(req)
 		}))
 		assert.NilError(t, err)
 		body, err := client.ServiceLogs(context.Background(), "service_id", logCase.options)

client/service_remove_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -44,10 +42,7 @@ func TestServiceRemove(t *testing.T) {
 		if err := assertRequest(req, http.MethodDelete, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/service_update_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -74,10 +72,7 @@ func TestServiceUpdate(t *testing.T) {
 			if version != updateCase.expectedVersion {
 				return nil, fmt.Errorf("version not set in URL query properly, expected '%s', got %s", updateCase.expectedVersion, version)
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte("{}"))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "{}")(req)
 		}))
 		assert.NilError(t, err)
 

client/swarm_get_unlock_key_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -32,20 +29,9 @@ func TestSwarmGetUnlockKey(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-
-		key := swarm.UnlockKeyResponse{
+		return mockJSONResponse(http.StatusOK, nil, swarm.UnlockKeyResponse{
 			UnlockKey: unlockKey,
-		}
-
-		b, err := json.Marshal(key)
-		if err != nil {
-			return nil, err
-		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/swarm_init_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -27,10 +25,7 @@ func TestSwarmInit(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(`"body"`))),
-		}, nil
+		return mockJSONResponse(http.StatusOK, nil, "node-id")(req)
 	}))
 	assert.NilError(t, err)
 
@@ -38,5 +33,5 @@ func TestSwarmInit(t *testing.T) {
 		ListenAddr: "0.0.0.0:2377",
 	})
 	assert.NilError(t, err)
-	assert.Check(t, is.Equal(result.NodeID, "body"))
+	assert.Check(t, is.Equal(result.NodeID, "node-id"))
 }

client/swarm_inspect_test.go

@@ -1,9 +1,6 @@
 package client
 
 import (
-	"bytes"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -27,18 +24,11 @@ func TestSwarmInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(swarm.Swarm{
+		return mockJSONResponse(http.StatusOK, nil, swarm.Swarm{
 			ClusterInfo: swarm.ClusterInfo{
 				ID: "swarm_id",
 			},
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/swarm_join_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -27,10 +25,7 @@ func TestSwarmJoin(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/swarm_leave_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -46,10 +44,7 @@ func TestSwarmLeave(t *testing.T) {
 			if force != leaveCase.expectedForce {
 				return nil, fmt.Errorf("force not set in URL query properly. expected '%s', got %s", leaveCase.expectedForce, force)
 			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-			}, nil
+			return mockResponse(http.StatusOK, nil, "")(req)
 		}))
 		assert.NilError(t, err)
 

client/swarm_unlock_test.go

@@ -1,9 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"io"
 	"net/http"
 	"testing"
 
@@ -27,10 +25,7 @@ func TestSwarmUnlock(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/swarm_update_test.go

@@ -1,8 +1,6 @@
 package client
 
 import (
-	"bytes"
-	"io"
 	"net/http"
 	"testing"
 
@@ -26,10 +24,7 @@ func TestSwarmUpdate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte(""))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "")(req)
 	}))
 	assert.NilError(t, err)
 

client/system_disk_usage_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -28,22 +25,12 @@ func TestDiskUsage(t *testing.T) {
 			return nil, err
 		}
 
-		du := system.DiskUsage{
+		return mockJSONResponse(http.StatusOK, nil, system.DiskUsage{
 			LayersSize: int64(100),
 			Images:     nil,
 			Containers: nil,
 			Volumes:    nil,
-		}
-
-		b, err := json.Marshal(du)
-		if err != nil {
-			return nil, err
-		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 	_, err = client.DiskUsage(context.Background(), DiskUsageOptions{})

client/system_info_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -22,12 +19,7 @@ func TestInfoServerError(t *testing.T) {
 }
 
 func TestInfoInvalidResponseJSONError(t *testing.T) {
-	client, err := NewClientWithOpts(WithMockClient(func(req *http.Request) (*http.Response, error) {
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("invalid json"))),
-		}, nil
-	}))
+	client, err := NewClientWithOpts(WithMockClient(mockResponse(http.StatusOK, nil, "invalid json")))
 	assert.NilError(t, err)
 	_, err = client.Info(context.Background())
 	assert.Check(t, is.ErrorContains(err, "invalid character"))
@@ -39,19 +31,10 @@ func TestInfo(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		info := &system.Info{
+		return mockJSONResponse(http.StatusOK, nil, system.Info{
 			ID:         "daemonID",
 			Containers: 3,
-		}
-		b, err := json.Marshal(info)
-		if err != nil {
-			return nil, err
-		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 
@@ -68,7 +51,7 @@ func TestInfoWithDiscoveredDevices(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		info := &system.Info{
+		return mockJSONResponse(http.StatusOK, nil, system.Info{
 			ID:         "daemonID",
 			Containers: 3,
 			DiscoveredDevices: []system.DeviceInfo{
@@ -81,16 +64,7 @@ func TestInfoWithDiscoveredDevices(t *testing.T) {
 					ID:     "vendor.com/gpu=1",
 				},
 			},
-		}
-		b, err := json.Marshal(info)
-		if err != nil {
-			return nil, err
-		}
-
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(b)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/task_inspect_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -43,16 +40,9 @@ func TestTaskInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(swarm.Task{
+		return mockJSONResponse(http.StatusOK, nil, swarm.Task{
 			ID: "task_id",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/task_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -57,21 +54,10 @@ func TestTaskList(t *testing.T) {
 					return nil, fmt.Errorf("%s not set in URL query properly. Expected '%s', got %s", key, expected, actual)
 				}
 			}
-			content, err := json.Marshal([]swarm.Task{
-				{
-					ID: "task_id1",
-				},
-				{
-					ID: "task_id2",
-				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			return mockJSONResponse(http.StatusOK, nil, []swarm.Task{
+				{ID: "task_id1"},
+				{ID: "task_id2"},
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/volume_create_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
-	"io"
 	"net/http"
 	"testing"
 
@@ -29,19 +26,11 @@ func TestVolumeCreate(t *testing.T) {
 		if err := assertRequest(req, http.MethodPost, expectedURL); err != nil {
 			return nil, err
 		}
-
-		content, err := json.Marshal(volume.Volume{
+		return mockJSONResponse(http.StatusOK, nil, volume.Volume{
 			Name:       "volume",
 			Driver:     "local",
 			Mountpoint: "mountpoint",
-		})
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		})(req)
 	}))
 	assert.NilError(t, err)
 

client/volume_inspect_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
-	"encoding/json"
 	"errors"
-	"io"
 	"net/http"
 	"testing"
 
@@ -56,14 +53,7 @@ func TestVolumeInspect(t *testing.T) {
 		if err := assertRequest(req, http.MethodGet, expectedURL); err != nil {
 			return nil, err
 		}
-		content, err := json.Marshal(expected)
-		if err != nil {
-			return nil, err
-		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader(content)),
-		}, nil
+		return mockJSONResponse(http.StatusOK, nil, expected)(req)
 	}))
 	assert.NilError(t, err)
 

client/volume_list_test.go

@@ -1,11 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -54,21 +51,14 @@ func TestVolumeList(t *testing.T) {
 			if actualFilters != listCase.expectedFilters {
 				return nil, fmt.Errorf("filters not set in URL query properly. Expected '%s', got %s", listCase.expectedFilters, actualFilters)
 			}
-			content, err := json.Marshal(volume.ListResponse{
+			return mockJSONResponse(http.StatusOK, nil, volume.ListResponse{
 				Volumes: []*volume.Volume{
 					{
 						Name:   "volume",
 						Driver: "local",
 					},
 				},
-			})
-			if err != nil {
-				return nil, err
-			}
-			return &http.Response{
-				StatusCode: http.StatusOK,
-				Body:       io.NopCloser(bytes.NewReader(content)),
-			}, nil
+			})(req)
 		}))
 		assert.NilError(t, err)
 

client/volume_prune_test.go

@@ -1,10 +1,7 @@
 package client
 
 import (
-	"bytes"
-	"encoding/json"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -75,17 +72,10 @@ func TestVolumePrune(t *testing.T) {
 				if actualFilters != tc.expectedFilters {
 					return nil, fmt.Errorf("filters not set in URL query properly. Expected '%s', got %s", tc.expectedFilters, actualFilters)
 				}
-				content, err := json.Marshal(volume.PruneReport{
+				return mockJSONResponse(http.StatusOK, nil, volume.PruneReport{
 					VolumesDeleted: []string{"volume"},
 					SpaceReclaimed: 12345,
-				})
-				if err != nil {
-					return nil, err
-				}
-				return &http.Response{
-					StatusCode: http.StatusOK,
-					Body:       io.NopCloser(bytes.NewReader(content)),
-				}, nil
+				})(req)
 			}))
 			assert.NilError(t, err)
 

client/volume_remove_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"testing"
 
@@ -52,10 +50,7 @@ func TestVolumeRemove(t *testing.T) {
 			return nil, fmt.Errorf("expected force=1, got %s", v)
 		}
 
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)
 

client/volume_update_test.go

@@ -1,10 +1,8 @@
 package client
 
 import (
-	"bytes"
 	"context"
 	"fmt"
-	"io"
 	"net/http"
 	"strings"
 	"testing"
@@ -44,10 +42,7 @@ func TestVolumeUpdate(t *testing.T) {
 		if !strings.Contains(req.URL.RawQuery, expectedVersion) {
 			return nil, fmt.Errorf("expected query to contain '%s', got '%s'", expectedVersion, req.URL.RawQuery)
 		}
-		return &http.Response{
-			StatusCode: http.StatusOK,
-			Body:       io.NopCloser(bytes.NewReader([]byte("body"))),
-		}, nil
+		return mockResponse(http.StatusOK, nil, "body")(req)
 	}))
 	assert.NilError(t, err)