Module 01 · 35 min
Build the vocabulary and reasoning that explain why testing exists, what it can reveal, and what it cannot prove.
Written and reviewed by ShiftQA Labs QA Education Team · Updated September 2, 2026
Testing provides information about quality and risk. It can reveal failures, prevent defects through early review, support decisions, and build confidence. Testing does not prove that a product has no defects; it reduces uncertainty using evidence.
Testing may expose a failure caused by a defect. Debugging finds, analyzes, and removes the cause. A tester can reproduce and report the failure; a developer commonly performs debugging and then the changed product is tested again.
Testing shows the presence, not the absence, of defects. Exhaustive testing is impossible. Early testing saves time and money. Defects cluster. Repeating the same tests loses effectiveness. Testing depends on context. A defect-free product can still fail users if it solves the wrong problem.
Knowledge check
These original questions reinforce the lesson. They are not official ISTQB exam questions.
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Unofficial ISTQB preparation by ShiftQA Labs. Use the official CTFL syllabus and sample materials as the source of truth.
