What does one good test look like?
A good test has three parts: set up state, trigger an action, check the visible outcome.
One behavior, one test
Arrange the starting state, act on it, then assert what the user can see. A test that checks two things at once hides which one failed.
I want to test [describe the behavior]. What single user behavior does this test actually check, and what visible outcome in the browser proves it passed?
Then the three parts are easy
Once you know the behavior, the parts are obvious: set up state, do one action, assert what shows up.
Write a Playwright test in arrange-act-assert for [describe the behavior] in a Next.js App Router project, with one comment marking each of the three parts.
A good test arranges state, acts once, and asserts what the user can see. One behavior per test keeps failures readable.
Additional Resources
Explore these carefully curated resources to deepen your understanding and practice the concepts covered in this lesson.