What is it
Software testing covers the systematic techniques used to verify that a program behaves correctly — including unit testing, integration testing, test-driven development, and strategies for choosing which test cases actually catch meaningful bugs.
Why it matters
Untested code is a liability the moment it's written, even if it currently works — testing is what gives a development team the confidence to change and extend a system without constantly fearing they've silently broken something elsewhere.
Exam tip
When designing test cases, deliberately include boundary values (the smallest, largest, and edge-case inputs) rather than only typical ones — the majority of real-world bugs live at boundaries, not in the middle of the normal input range.
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