private ImageIcon makeQuandrantIcon(int w, int h, Color bgColor, Color lineColor) {
		BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_ARGB);
		Graphics g = bi.getGraphics();
		g.setColor(bgColor);
		g.fillRect(0, 0, w, h);
		g.setColor(lineColor);
		g.drawLine(w / 2, 0, w / 2, h);
		g.drawLine(0, h / 2, w, h / 2);
		g.dispose();
		return new ImageIcon(bi);
	}
Minimal tests for MultiIconBuilder.  Doesn't test the produced images, just that it didn't cause an exception.
<p>
The showXYZ() methods are present so a human can run them as a test and see the output
Ghidra/Framework/Gui/src/test/java/resources/icons/MultiIconBuilderTest.java