TestBuildUserNamespaceValidateCapabilitiesAreV2: verify build completed

Check if the `docker build` completed successfully before continuing.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit fa480403c75c90880a6bc79bab9e10b012379006)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

integration/build/build_userns_linux_test.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/integration/internal/container"
+	"github.com/docker/docker/pkg/jsonmessage"
 	"github.com/docker/docker/pkg/stdcopy"
 	"github.com/docker/docker/testutil/daemon"
 	"github.com/docker/docker/testutil/fakecontext"
@@ -66,17 +67,10 @@ func TestBuildUserNamespaceValidateCapabilitiesAreV2(t *testing.T) {
 		})
 	assert.NilError(t, err)
 	defer resp.Body.Close()
-	buf := make([]byte, 1024)
-	for {
-		n, err := resp.Body.Read(buf)
-		if err != nil && err != io.EOF {
-			t.Fatalf("Error reading ImageBuild response: %v", err)
-			break
-		}
-		if n == 0 {
-			break
-		}
-	}
+
+	buf := bytes.NewBuffer(nil)
+	err = jsonmessage.DisplayJSONMessagesStream(resp.Body, buf, 0, false, nil)
+	assert.NilError(t, err)
 
 	reader, err := clientUserRemap.ImageSave(ctx, []string{imageTag})
 	assert.NilError(t, err, "failed to download capabilities image")
@@ -106,16 +100,9 @@ func TestBuildUserNamespaceValidateCapabilitiesAreV2(t *testing.T) {
 	loadResp, err := clientNoUserRemap.ImageLoad(ctx, tarReader, false)
 	assert.NilError(t, err, "failed to load image tar file")
 	defer loadResp.Body.Close()
-	for {
-		n, err := loadResp.Body.Read(buf)
-		if err != nil && err != io.EOF {
-			t.Fatalf("Error reading ImageLoad response: %v", err)
-			break
-		}
-		if n == 0 {
-			break
-		}
-	}
+	buf = bytes.NewBuffer(nil)
+	err = jsonmessage.DisplayJSONMessagesStream(loadResp.Body, buf, 0, false, nil)
+	assert.NilError(t, err)
 
 	cid := container.Run(ctx, t, clientNoUserRemap,
 		container.WithImage(imageTag),