What is Software Testing - Complete Guide

What is Software Testing?

Software testing is the process of verifying that software works correctly and meets requirements. It catches bugs before users do, improving quality and reliability.

Levels of Testing

Level	Tests
Unit	Individual functions
Integration	Components together
E2E	Full user flows
Acceptance	Business requirements

Manual vs Automated

• Manual — a human clicks through the app.
• Automated — code tests code, repeatable and fast.

A Simple Unit Test

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

test("adds numbers", () => {
  expect(add(2, 3)).toBe(5);
});

Why Test?

• Catch bugs early (cheaper to fix).
• Refactor with confidence.
• Document expected behavior.

FAQs

Popular testing tools?

Jest, Vitest (JS), PyTest (Python), JUnit (Java), Cypress/Playwright (E2E). More in our Testing guides.

How much should I test?

Focus on critical paths; aim for meaningful coverage, not 100%.