### Question:
MdcAdvisor extends AbstractAdvisor<MethodMdc> { static MdcAdvisor newInstance(List<MethodMdc> methodMdcs, ExpressionEvaluator expressionEvaluator) { return methodMdcs.isEmpty() ? null : new MdcAdvisor(methodMdcs, expressionEvaluator); } private  MdcAdvisor(List<MethodMdc> methodMdcs,
                       ExpressionEvaluator expressionEvaluator); @Override Object invoke(MethodInvocation invocation);  }### Answer:
@Test public void newInstance() { List<MethodMdc> methodMdcs = emptyList(); ExpressionEvaluator expressionEvaluator = mock(ExpressionEvaluator.class); MdcAdvisor mdcAdvisor = MdcAdvisor.newInstance(methodMdcs, expressionEvaluator); assertNull(mdcAdvisor); }