Introduction to Software Testing
Understand what software testing is, why it's important, and how it fits into the software development process
45 min•By Priygop Team•Last updated: Feb 2026
What is Software Testing?
Software testing is the process of evaluating and verifying that a software application or system does what it is supposed to do. It involves executing software components using a manual or automated approach to evaluate one or more properties of interest.
Why is Software Testing Important?
- Quality Assurance: Ensures software meets quality standards
- Bug Detection: Identifies defects before production
- Cost Reduction: Early bug detection saves money
- User Satisfaction: Delivers reliable software to users
- Risk Mitigation: Reduces business and technical risks
- Compliance: Meets regulatory and industry standards
Software Testing Principles
- Testing shows presence of defects
- Exhaustive testing is impossible
- Early testing saves time and money
- Defects cluster together
- Beware of the pesticide paradox
- Testing is context dependent
- Absence of errors is a fallacy
Testing vs Debugging
Example
// Testing vs Debugging
// Testing: Finding defects
function testLogin() {
const result = login("user", "password");
assert(result.success === true);
assert(result.message === "Login successful");
}
// Debugging: Fixing defects
function login(username, password) {
// Bug: Missing validation
if (!username || !password) {
return { success: false, message: "Invalid credentials" };
}
// Fixed: Added proper validation
if (username.length < 3) {
return { success: false, message: "Username too short" };
}
return { success: true, message: "Login successful" };
}