Bug 266146 [CSS] JUnit for: Property retrieval must check instanceof and return null
tests/org.eclipse.e4.ui.tests.css.swt/src/org/eclipse/e4/ui/tests/css/swt/ShellTest.java
static final RGB RED = new RGB(255, 0, 0);
	static final RGB GREEN = new RGB(0, 255, 0);
	static final RGB BLUE = new RGB(0, 0, 255);
		
	protected Shell createTestShell(String styleSheet) {
		Display display = Display.getDefault();
		CSSEngine engine = createEngine(styleSheet, display);
		
		
		Shell shell = new Shell(display, SWT.SHELL_TRIM);
		FillLayout layout = new FillLayout();
		shell.setLayout(layout);
		Composite panel = new Composite(shell, SWT.NONE);
		panel.setLayout(new FillLayout());
		
		engine.applyStyles(shell, true);
		shell.pack();
		return shell;
	}