test-driven-development

Write a failing ERT test that describes the desired behavior, then implement only enough code to make it pass. Iterate this red-green-refactor cycle to incrementally prove behavior and guide robust Elisp.

The red-green-refactor cycle for Elisp unit testing involves writing a failing ERT test, implementing minimal code to pass it, and refactoring safely while keeping tests green. This process prevents defects by defining expected behavior upfront.

Yes, you can use ERT to validate code paths and edge cases in Emacs Lisp. By encoding expected behavior as tests before coding, you ensure features and bugfixes remain robust throughout iterative refactoring.

Test-driven development works for bugfixes in Emacs Lisp by first writing an ERT test that captures the expected behavior and fails with the current bug, then implementing the fix to make the test pass.

You should avoid enforcing a test suite for trivial Emacs Lisp scripts where setup overhead outweighs the benefit, but TDD remains essential for complex packages requiring safe refactoring and edge case validation.