Introduction to Software Testing

Software testing is the process of evaluating a system to find defects and confirm it behaves as intended, protecting users, businesses, and reputations from the cost of shipping broken software.

Why Testing Matters

Every piece of software has bugs — the question is whether they're found before or after release. A defect caught during development might cost minutes to fix; the same defect discovered in production, after affecting real customers, can cost a business far more in lost trust, revenue, and emergency engineering time.

Testing isn't just about clicking buttons to see if they work — it's a disciplined, evidence-based practice for building confidence that software does what it's supposed to do, and doesn't do what it shouldn't.

The Tester's Mindset

Good testers approach software with structured curiosity: not just "does this work when used correctly" but "what happens at the edges, under stress, or when used in ways the developer didn't anticipate". This mindset — deliberately trying to break things in a controlled, documented way — is what separates testing from simply using software.

Common Mistakes

• Assuming testing means simply running the software once and confirming it 'looks right'.
• Testing only the 'happy path' (expected, correct usage) and skipping edge cases and invalid input.
• Treating testing as something that only happens at the very end of a project, right before release.
• Believing that testing can prove software has zero bugs — testing can reveal defects, but can never prove their complete absence.