Testing JavaScript and DOM with DOM Testing Library

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Best Practices for Testing with Testing Library

To ensure that our tests are efficient, maintainable, and robust, it is important to follow some best practices when working with DOM Testing Library. In this chapter, we will discuss a series of recommendations and strategies that will help you write high-quality tests.

Writing Clear and Readable Tests

Descriptive names: Ensure that your test names clearly describe what they are verifying.
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Comments when necessary: Use comments to explain complex logic or special cases that are not directly evident.
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Keeping Test Code Simple

Avoid complex logic in tests: Tests should be as simple as possible. Avoid loops, conditionals, and complex logic.
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Reuse common setups: Avoid repeating the same setup code in each test by using beforeEach and helpers.
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Ensuring Test Independence

Do not depend on previous tests: Each test should be able to run independently and should not depend on state modified by another test.
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Use mocks to isolate components: Mock dependencies to isolate the component you are testing.
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Using Robust Selectors

Prefer selectors by role and labelText: These selectors better emulate how users interact with the UI and are more robust against design changes.
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Avoid selectors by ID or classes: ID or class-based selectors are more prone to breaking with minor design changes.
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Validating Built-in Accessibility

Use jest-axe for automated accessibility: Incorporate jest-axe in your tests to automatically validate accessibility best practices.
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Ensuring Reliable Asynchronous Tests

Use waitFor and findBy: Ensure that your asynchronous tests properly wait for DOM changes.
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Mocking time operations: Use jest.useFakeTimers() to control and speed up timers in your tests.
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Code Coverage Strategies

Coverage configuration: Set up Jest to collect and generate code coverage reports.
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Review and act on coverage: Regularly review coverage reports and focus on covering critical areas of your application.

Examples of Best Practices in Tests

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[Placeholder for explanatory image: Diagram illustrating best practices from writing clear and readable tests to validating accessibility and ensuring reliable asynchronous tests]

Conclusion

By following these best practices, you can write more robust, clear, and maintainable tests that not only ensure the correct functionality of your code but also improve the overall quality and user experience of your application.

In the next chapter, we will discuss how to debug failing tests in Testing Library to quickly identify and resolve issues.

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