如何为自定义SWT-Column-Ratio-Layout编写JUnit测试？

import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.junit.Assert;
import org.junit.Test;

public class SWTColumnRatioLayoutTest {

    @Test
    public void testLayout() {
        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setLayout(new GridLayout());

        // Apply custom SWT-Column-Ratio-Layout to shell
        SWTColumnRatioLayout layout = new SWTColumnRatioLayout(new int[] { 1, 2, 1 });
        shell.setLayout(layout);

        // Create widgets and add them to shell
        // ...

        // Set layout data for widgets
        // ...

        // Assert the expected layout data
        Assert.assertEquals(new GridData(GridData.FILL, GridData.FILL, true, true), widget1.getLayoutData());
        Assert.assertEquals(new GridData(GridData.FILL, GridData.FILL, true, true), widget2.getLayoutData());
        Assert.assertEquals(new GridData(GridData.FILL, GridData.FILL, true, true), widget3.getLayoutData());

        shell.dispose();
        display.dispose();
    }
}