Actually invoke SetCell from dummyScreen.Print

layout_test.go

@@ -33,7 +33,7 @@ func (d dummyScreen) Close() error {
 }
 
 func (d dummyScreen) Print(args PrintArgs) int {
-	return len(args.Msg)
+	return screenPrint(d, args)
 }
 
 func (d dummyScreen) SendEvent(e termbox.Event) {

screen.go

@@ -99,6 +99,10 @@ type PrintArgs struct {
 }
 
 func (t Termbox) Print(args PrintArgs) int {
+	return screenPrint(t, args)
+}
+
+func screenPrint(t Screen, args PrintArgs) int {
 	var written int
 
 	bg := args.Bg