Why not just do unit tests instead of integration tests? Because you want to create a system that provides feedback on the entire end to end process. You subsid

Why not just do unit tests instead of integration tests? Because you want to create a system that provides feedback on the entire end to end process. You subsidize purchases because The thing you want to incentivize is not making solar panels, but bringing solar panels all the way to market. You are trying to get the market off the ground, not just the technology.