public void WhenEntityIsInvalidThenThrowExceptionAndDontSave()
{
//Arrange
var album = new Album();
var daoAlbum = new DaoStub <Album>().AddEntity(album);
var validator = new Mock <IEntityValidator>();
validator.Setup(v => v.IsValid(album)).Returns(false);
var model = new AlbumManager(daoAlbum, validator.Object);
//Act
model.Executing(am => am.Save(album))
.Throws <InvalidOperationException>(); //assert
//assert
daoAlbum.Mock.Verify(da => da.MakePersistent(album), Times.Never());
}