Question

I’ve done a small test and in the second test I get an assertion error (0 instead of 1):

package tests;

import static org.junit.Assert.*;
import org.junit.Test;
import javax.swing.*;

public class MenuTest {

    @Test
    public void testElementsAddition() {
        JMenuItem mItem1 = new JMenuItem();
        JMenuItem mItem2 = new JMenuItem();
        JMenu menu = new JMenu();

        mItem1.add(mItem2);
        assertEquals(1, mItem1.getComponentCount());

        menu.add(mItem1);
        assertEquals(1, menu.getComponentCount());
    }
}

Any Ideas why this might happen?

Answer 1

This occurs because the menu item isn’t actually added to the JMenu itself, but is added to a popup menu internally, there is actually nothing added to the menu.

I think you will want to use JMenu#getItemCount, which “Returns the number of items on the menu, including separators” or, preferably, JMenu#getMenuComponentCount