Introduction to Unit Testing

What is Unit Testing?

Unit testing is a software testing technique where individual units or components of a software are tested in isolation. The goal is to validate that each unit of the software performs as expected.

Unit tests are usually automated and written in the same programming language as the application code. They help ensure that changes and additions to code do not break existing functionality.

Why Unit Testing?

• Improves code quality and reliability.
• Facilitates code refactoring.
• Helps identify bugs early in the development process.
• Acts as documentation for the code.

How to Unit Test

To create a unit test, follow these steps:

1. Choose a testing framework (e.g., Jest for JavaScript, JUnit for Java).
2. Write a test case for a specific function or method.
3. Run the test case and review the results.
4. Refactor the code as necessary and rerun the tests.

Here is a simple example of a unit test in JavaScript using Jest:

function add(a, b) {
    return a + b;
}

test('adds 1 + 2 to equal 3', () => {
    expect(add(1, 2)).toBe(3);
});
                

Best Practices

• Write tests before writing code (Test-Driven Development).
• Keep tests small and focused on one aspect of functionality.
• Use clear and descriptive names for test cases.
• Run tests frequently to catch issues early.

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