Library needs tests. Ideally, of two kinds:
- Unit tests for code correctness: Check if output types are what they are supposed to be and crash early if they're not.
- Physics tests for algorithm correctness: Check if the methods give good enough results. Probably the easiest way is to check against analytical solutions known for simple problems, e.g., linear chains, free electron gas, 2-band graphene, etc.
Library needs tests. Ideally, of two kinds: