public void GetMessage()
{
var writerMock = MockRepository.GenerateMock <TextMessageWriter>();
writerMock.Expect(mock => mock.Write("Expected: ExpectedName but was: First, Second"));
writerMock.Replay();
var constraint = new EnumValueInfoListContentsConstraint("ExpectedName");
PrivateInvoke.SetNonPublicField(constraint, "actual", _list);
constraint.WriteMessageTo(writerMock);
writerMock.VerifyAllExpectations();
}