Insights on Testing Elixir Code Effectively

The author reflects on his journey through testing Elixir code, particularly related to his work on the ExFileBrowser project. He contrasts informal testing in IEx with structured testing using ExUnit, advocating for the latter as essential for maintainable code. Key points include the importance of spot-check testing in IEx for rapid feedback during development, but recognizing that this approach does not scale and lacks documentation. He argues against the necessity of testing trivial functions directly and highlights the importance of focusing tests on the public API contract of modules. Additionally, the author suggests that integration tests are paramount, and one should be wary of dogmatic rules regarding testing completeness or coverage. The piece emphasizes that effective testing shouldn’t stifle creativity and that understanding the contracts the code presents to users is crucial for successful software engineering in Elixir.