public async Task ShowCakeDetails_WithInValidId_ShouldReturnNull()
{
//Arrange
var db = this.SetDb();
await this.SeedProducts(db);
var repo = new Repository <Product>(db);
var service = new CakeService(null, repo, this.Mapper);
//Act
var cakeDetails = await service.ShowCakeDetails(3);
//Assert
Assert.Null(cakeDetails);
}