refactor: use named constants for port and exit code in tests

Signed-off-by: Ogulcan Aydogan <ogulcanaydogan@hotmail.com>

Author: ogulcanaydogan

cmd/nerdctl/container/multi_platform_linux_test.go

@@ -33,6 +33,9 @@ import (
 	"github.com/containerd/nerdctl/v2/pkg/testutil/nettestutil"
 )
 
+// randomPort asks the registry helpers to acquire a free port automatically.
+const randomPort = 0
+
 // requireMultiPlatformExec skips the test when the host cannot execute
 // linux/amd64, linux/arm64 and linux/arm/v7 images (e.g. no binfmt_misc).
 var requireMultiPlatformExec = &test.Requirement{
@@ -63,7 +66,8 @@ func assertMultiPlatformRun(helpers test.Helpers, image string) {
 		helpers.T().Log(fmt.Sprintf("Testing platform %q (%q)", plat, expectedUnameM))
 		helpers.Command("run", "--rm", "--platform="+plat, image, "uname", "-m").
 			Run(&test.Expected{
-				Output: expect.Equals(expectedUnameM + "\n"),
+				ExitCode: expect.ExitCodeSuccess,
+				Output:   expect.Equals(expectedUnameM + "\n"),
 			})
 	}
 }
@@ -105,7 +109,7 @@ func TestMultiPlatformBuildPush(t *testing.T) {
 	var reg *registry.Server
 
 	testCase.Setup = func(data test.Data, helpers test.Helpers) {
-		reg = nerdtest.RegistryWithNoAuth(data, helpers, 0 /* random port */, false)
+		reg = nerdtest.RegistryWithNoAuth(data, helpers, randomPort, false)
 		reg.Setup(data, helpers)
 		imageName := fmt.Sprintf("localhost:%d/%s:latest", reg.Port, data.Identifier())
 		data.Labels().Set("image", imageName)
@@ -151,7 +155,7 @@ func TestMultiPlatformBuildPushNoRun(t *testing.T) {
 	var reg *registry.Server
 
 	testCase.Setup = func(data test.Data, helpers test.Helpers) {
-		reg = nerdtest.RegistryWithNoAuth(data, helpers, 0 /* random port */, false)
+		reg = nerdtest.RegistryWithNoAuth(data, helpers, randomPort, false)
 		reg.Setup(data, helpers)
 		imageName := fmt.Sprintf("localhost:%d/%s:latest", reg.Port, data.Identifier())
 		data.Labels().Set("image", imageName)
@@ -196,7 +200,7 @@ func TestMultiPlatformPullPushAllPlatforms(t *testing.T) {
 	var reg *registry.Server
 
 	testCase.Setup = func(data test.Data, helpers test.Helpers) {
-		reg = nerdtest.RegistryWithNoAuth(data, helpers, 0 /* random port */, false)
+		reg = nerdtest.RegistryWithNoAuth(data, helpers, randomPort, false)
 		reg.Setup(data, helpers)
 		pushImageName := fmt.Sprintf("localhost:%d/%s:latest", reg.Port, data.Identifier())
 		data.Labels().Set("image", pushImageName)