public void TestFavouriting()
{
client.Setup(c => c.User)
.Returns(() => new Mock <IUser>().Object);
Artist artist = new Artist()
{
Id = kArtistId,
};
artist.Deserialize(client.Object);
artist.AddArtistToFavorite();
artist.RemoveArtistFromFavorite();
client.Verify(c => c.User, Times.Exactly(2));
}