Add RunAsSubcommand to keep API unchanged

app.go

@@ -305,6 +305,12 @@ func (a *App) RunContext(ctx context.Context, arguments []string) (err error) {
 	return a.rootCommand.Run(cCtx, arguments...)
 }
 
+// This is a stub function to keep public API unchanged from old code
+// No one should really use this. Always use a.Run to execute app
+func (a *App) RunAsSubcommand(ctx *Context) (err error) {
+	return a.RunContext(ctx.Context, ctx.Args().Slice())
+}
+
 func (a *App) suggestFlagFromError(err error, command string) (string, error) {
 	flag, parseErr := flagFromError(err)
 	if parseErr != nil {

help_test.go

@@ -1050,7 +1050,6 @@ func newContextFromStringSlice(ss []string) *Context {
 	return &Context{flagSet: set}
 }
 
-/*
 func TestHideHelpCommand_RunAsSubcommand(t *testing.T) {
 	app := &App{
 		HideHelpCommand: true,
@@ -1097,7 +1096,6 @@ func TestHideHelpCommand_RunAsSubcommand_False(t *testing.T) {
 		t.Errorf("Run returned unexpected error: %v", err)
 	}
 }
-*/
 
 func TestHideHelpCommand_WithSubcommands(t *testing.T) {
 	app := &App{