Disable checkpoint/restore unit tests for docker

Currently, nerdctl CI uses docker 28.0.4, while docker version 28.x
has a known regression that breaks Checkpoint/Restore functionality.
The issue is tracked in the moby/moby project as moby/moby#50750.

Signed-off-by: ChengyuZhu6 <[email protected]>

Author: ChengyuZhu6

cmd/nerdctl/checkpoint/checkpoint_create_linux_test.go

@@ -21,6 +21,7 @@ import (
 	"testing"
 
 	"github.com/containerd/nerdctl/mod/tigron/expect"
+	"github.com/containerd/nerdctl/mod/tigron/require"
 	"github.com/containerd/nerdctl/mod/tigron/test"
 
 	"github.com/containerd/nerdctl/v2/pkg/rootlessutil"
@@ -33,6 +34,9 @@ func TestCheckpointCreateErrors(t *testing.T) {
 		t.Skip("test skipped for rootless containers")
 	}
 	testCase := nerdtest.Setup()
+	// Docker version 28.x has a known regression that breaks Checkpoint/Restore functionality.
+	// The issue is tracked in the moby/moby project as https://github.com/moby/moby/issues/50750.
+	testCase.Require = require.Not(nerdtest.Docker)
 	testCase.SubTests = []*test.Case{
 		{
 			Description: "too-few-arguments",
@@ -76,6 +80,9 @@ func TestCheckpointCreate(t *testing.T) {
 		checkpointDir  = "/dir/foo"
 	)
 	testCase := nerdtest.Setup()
+	// Docker version 28.x has a known regression that breaks Checkpoint/Restore functionality.
+	// The issue is tracked in the moby/moby project as https://github.com/moby/moby/issues/50750.
+	testCase.Require = require.Not(nerdtest.Docker)
 	testCase.SubTests = []*test.Case{
 		{
 			Description: "leave-running=true",

cmd/nerdctl/container/container_start_linux_test.go

@@ -26,6 +26,7 @@ import (
 	"gotest.tools/v3/assert"
 
 	"github.com/containerd/nerdctl/mod/tigron/expect"
+	"github.com/containerd/nerdctl/mod/tigron/require"
 	"github.com/containerd/nerdctl/mod/tigron/test"
 	"github.com/containerd/nerdctl/mod/tigron/tig"
 
@@ -86,6 +87,9 @@ func TestStartWithCheckpoint(t *testing.T) {
 
 	testCase := nerdtest.Setup()
 
+	// Docker version 28.x has a known regression that breaks Checkpoint/Restore functionality.
+	// The issue is tracked in the moby/moby project as https://github.com/moby/moby/issues/50750.
+	testCase.Require = require.Not(nerdtest.Docker)
 	testCase.Setup = func(data test.Data, helpers test.Helpers) {
 		helpers.Ensure("run", "-d", "--name", data.Identifier(), testutil.CommonImage, "sleep", "infinity")
 		helpers.Ensure("checkpoint", "create", data.Identifier(), data.Identifier()+"-checkpoint")