As you write tests for React applications, focusing on reliability and clarity is essential. Reliable tests consistently pass or fail based on the code's actual behavior, not on unpredictable factors.

To avoid flaky tests—those that sometimes pass and sometimes fail without code changes—stick to a few important guidelines:

• Avoid using timers or relying on asynchronous behavior unless absolutely necessary;
• Always wait for elements to appear or disappear using the appropriate utilities from React Testing Library;
• Minimize reliance on implementation details by testing user-visible behavior instead of checking internal state or private functions.

Your assertions should reflect what a real user would see or do, such as verifying that a button is visible or that a message appears after a click.

When writing assertions, make them as clear and specific as possible:

• Instead of checking for the presence of generic elements, assert for specific text, roles, or labels that match the user interface;
• This approach not only makes your tests more robust but also easier for others to understand and maintain.

Descriptive test names and comments play a crucial role in making your test suite readable and maintainable. A well-named test clearly states what behavior it is verifying, such as shows error message when login fails instead of a vague handles errors. This clarity helps anyone reading the tests quickly understand the purpose and expected outcome.

Adding concise comments can further clarify complex scenarios or the reasoning behind certain assertions, but avoid over-commenting when the test name and code are already self-explanatory. Ultimately, good names and comments reduce confusion, speed up debugging, and make onboarding new team members easier.