Unit Testing

Unit testing is a software development practice where individual components or functions of a program are tested in isolation. The purpose is to verify that each small piece of code—a "unit"—works exactly as intended before it's integrated with other parts of the application. This is typically done by developers as they write the code, and it helps to catch bugs very early in the development cycle, making them easier and cheaper to fix.

Example: A developer writes a function for a login page that checks if a password meets certain security requirements, like a minimum length and the presence of special characters. Before combining this function with the rest of the application, they perform unit testing. They would create tests that call this function with different inputs, such as:

• A password that is too short.
• A password that is long enough but has no special characters.
• A password that meets all the requirements.

The developer would then verify that the function returns the correct output for each case (e.g., false for the first two and true for the last). This ensures the function is reliable before it becomes part of the live login process.