What you need to know
Unit tests cannot verify that routing, browser rendering, forms, and backend responses work together. A small end-to-end suite can protect the paths users rely on most.
How to apply it
Choose one critical journey, use role- and label-based locators, wait for visible outcomes rather than arbitrary timeouts, and keep test data isolated. Capture traces when failures are difficult to reproduce.
Common mistake to avoid
Do not make every test depend on production data or fragile CSS selectors. Stable setup and accessible locators reduce flaky runs.