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/CSSTestCase.java
public CSSEngine createEngine(String styleSheet, Display display) {
		CSSEngine engine = new CSSSWTEngineImpl(display);
		
		engine.setErrorHandler(new CSSErrorHandler() {
			public void error(Exception e) {
				fail(e.getMessage());
			}
		});
		
		try {
			engine.parseStyleSheet(new StringReader(styleSheet));
		} catch (IOException e) {
			fail(e.getMessage());
		}
		return engine;
	}
}