Tester should perform testing
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in adhoc manner
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Based on the test cases
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with previous knowledge in testing without following the test steps of test case
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None of the above
Testing should be structured and based on predefined test cases to ensure coverage, repeatability, and traceability. Adhoc testing is unreliable and doesn't provide documented evidence. Even when using experience, you should follow documented test steps to maintain process discipline.
Formal software testing should follow documented test cases so that coverage is repeatable, traceable, and verifiable against requirements. Testing 'in an adhoc manner' or purely from memory/experience without following test steps sacrifices consistency and makes it hard to prove what was actually tested.