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📖 What is Defect (Fault/Bug)?

An imperfection or deficiency in a work product where it does not meet its requirements or specifications. A defect, if executed, may cause a failure.

🥋 Sensei Says:

"A defect does not always result in a failure. For example, a defect in a block of dead code will never be executed and thus never fail."

📚 Certification: Certified Tester Foundation Level (CTFL-v4.0)

🔑 What are the Key Concepts of Defect (Fault/Bug)?

▸ Static vs dynamic presence of a bug in a work product.
▸ The concept of 'latent' vs 'active' defects.
▸ Defect clustering and Pareto principle in software modules.

🎯 How does Defect (Fault/Bug) appear on the CTFL-v4.0 Exam?

A static analysis tool finds a variable that is initialized but never used. You must identify this as a defect rather than a failure.

Given a piece of dead code with a logical flaw, you are asked why it has never caused a failure in production.

❓ Frequently Asked Questions

Are bugs and defects the same thing?

Yes, ISTQB uses defect, fault, and bug interchangeably to refer to an imperfection in a work product.

Does every defect lead to a failure?

No, a defect must be executed under specific conditions to manifest as a failure. If those conditions are never met, the defect remains hidden.

Related Terms from Certified Tester Foundation Level

Experience-Based Testing Technique Impact Analysis Test Plan Control Flow Graph Error Guessing Test Execution Tool

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