DefaultMessageContext context = new DefaultMessageContext(messageSource);
Object object = new Object();
MessageContextErrors errors = new MessageContextErrors(context, "object", object, null, null);
MapBindingResult result = new MapBindingResult(new HashMap(), "object");
result.reject("bar", new Object[] { "boop" }, null);
result.rejectValue("field", "bar", new Object[] { "boop" }, null);
errors.addAllErrors(result);
Message msg = context.getAllMessages()[0];
assertEquals(null, msg.getSource());