Created: 2021-09-09 09:15
Write your types so you don’t have to write tests.
And then test what you cannot cover with types.
4. types solve 80% of the need for unit tests
The main reason you write unit tests is to ensure you call functions correctly, don’t make typos, and get test failures when a function’s API changes.
A static type system tells you all that on every keypress. Runs right in your IDE. Gives you red squiggly lines when something doesn’t match.
Types are unit tests with 100% coverage, if you squint a little.
You do need [integration] tests for behaviors.