The Art of Writing Better Tests: 9 Best Practices for JavaScript Developers
As a developer, you know that testing is an essential part of software engineering. It’s crucial for catching bugs, ensuring code quality, and serving as documentation for your team. However, many developers struggle with writing effective tests. In this article, we’ll explore nine best practices for JavaScript testing that will help you write better tests and make your team’s life easier.
Test Anatomy and Descriptions: The Foundation of Good Testing
A well-structured test is easy to read and understand. To achieve this, you can use the AAA pattern, which stands for Arrange, Act, and Assert. This pattern helps break down the logic inside tests into three parts, making them more manageable and easier to comprehend.
Another crucial aspect of test anatomy is writing detailed test descriptions. A simple yet effective approach is to use a three-layer system:
- Layer 1: Identify the unit or requirement being tested
- Layer 2: Describe the specific action or scenario being tested
- Layer 3: Outline the expected result
By following these guidelines, you’ll create tests that are easy to scan and understand.
Unit Testing Anti-Patterns: What to Avoid
When it comes to unit testing, there are some common mistakes to avoid. One of the most significant errors is testing private methods. Instead, focus on testing public methods, which will cover the implementation details of private methods.
Another anti-pattern is catching errors in tests using try…catch statements. This approach can lead to false positives and make it difficult to identify real issues. Instead, use built-in functions like Jest’s toThrow function to expect errors.
Test Preparation: Setting the Stage for Success
Test preparation is critical for creating effective tests. One common mistake is overusing helper libraries, which can lead to confusion and complexity. Remember, testing should be easy and fun! Aim to keep your testing setup simple and straightforward.
Another important consideration is the use of test preparation hooks like beforeAll and beforeEach. While these hooks can be useful, they can also create complexity and make it difficult to debug issues. Use them sparingly and only when necessary.
Conclusion
Writing better tests requires a combination of good test anatomy, avoiding common anti-patterns, and proper test preparation. By following these nine best practices, you’ll create tests that are easy to read, easy to maintain, and easy to understand. Remember, testing is an essential part of software engineering, and with the right approach, you can make it a breeze for yourself and your team.