Testing Fundamentals: Building and Verifying UI Components

Writing reliable code means knowing how to test it. If you have ever struggled to verify that your user interface behaves correctly when state changes, mastering component testing is your next step. In this written course, you will learn the foundational concepts of unit and component testing by building and testing a dynamic counter application. You will transition from understanding basic testing terminology to writing robust tests for conditional text rendering, button clicks, and state updates. What you will learn: Understand foundational testing terminology and the structure of a standard test suite; Write unit tests to verify conditional rendering logic, such as switching between singular and plural text based on state; Simulate user interactions like button clicks to test state decrementing and incrementing; Apply modern query strategies to find elements reliably using accessibility-first selectors; Organize and structure test files for better readability and maintainability. The course begins with core testing concepts and terminology before guiding you through step-by-step written exercises to implement and test a functional counter application. Designed for beginner developers who want to learn testing from scratch, this course requires no prior testing experience. Start reading today to build confidence in your code through the power of testing.