Testing Range and Boundary Conditions: The CORRECT Testing Guide

Many software bugs hide at the extreme edges of our code—where inputs are slightly too large, too small, or completely out of bounds. Understanding how to systematically test these range limits is critical to building reliable, production-ready software. In this text-based course, you will master the 'Range' aspect of the CORRECT testing methodology. You will transition from writing basic test cases to designing comprehensive, constraint-driven tests that ensure your applications behave predictably under any valid or invalid input range. What you'll learn: - Understand the core concepts of the CORRECT testing framework with a focus on range and boundaries - Identify critical boundary conditions and off-by-one errors before they reach production - Apply constraint-based testing techniques to validate minimum, maximum, and empty values - Practice writing parameterized tests to efficiently cover multiple input ranges - Explore modern approaches like basic property-based testing and type constraints to enforce valid data limits You will start by learning foundational testing terminology and the theory of boundary analysis. Then, you will progress through practical, written examples and exercises that demonstrate how to apply these constraints to real-world code. This course is designed for beginner software developers and QA engineers who want to write better unit tests. No advanced testing experience is required; a basic understanding of any programming language is helpful. Start reading today to secure your code against unexpected input ranges and edge-case errors.