add test case for container list

Signed-off-by: jason yang <jasonyangshadow@gmail.com>

internal/app/wwctl/container/list/root.go

@@ -2,18 +2,18 @@ package list
 
 import "github.com/spf13/cobra"
 
-var (
-	baseCmd = &cobra.Command{
-		DisableFlagsInUseLine: true,
-		Use:     "list [OPTIONS]",
-		Short:   "List imported Warewulf containers",
-		Long:    "This command will show you the containers that are imported into Warewulf.",
-		RunE:    CobraRunE,
-		Aliases: []string{"ls"},
-	}
-)
+type variables struct{}
 
 // GetRootCommand returns the root cobra.Command for the application.
 func GetCommand() *cobra.Command {
+	vars := variables{}
+	baseCmd := &cobra.Command{
+		DisableFlagsInUseLine: true,
+		Use:                   "list [OPTIONS]",
+		Short:                 "List imported Warewulf containers",
+		Long:                  "This command will show you the containers that are imported into Warewulf.",
+		RunE:                  CobraRunE(&vars),
+		Aliases:               []string{"ls"},
+	}
 	return baseCmd
 }