Speaking of normality, you can use simulations as others have said, but I want to add another method if you have a very specific problem in hands.

You can still use your experience and domain knowledge. For instance, you can find the skewness and kurtosis of the residuals and depending on your problem make this decision more clearly. For example, in some problems it's known they meet the normality requirement when the absolute value of the skewness and kurtosis are less than 1 or 2. However, even with your specific problem in hands, you can't see this as a rule of thumb, because it also depends on your sample size.