Intro — what this is and why it matters
Software Testing is the disciplined process of executing a program (or examining it) with the intent of finding defects and of evaluating whether the software meets its requirements. It is not about proving the program is perfect — as Edsger Dijkstra famously said, "Testing can show the presence of bugs, but never their absence." Testing gives us confidence, measured evidence that the software behaves as intended under the conditions we checked.
For Bangladeshi government IT recruitment exams (BCS technical, Bangladesh Bank / Combined Bank IT officer, BCC, and other IT-officer posts), Software Testing is one of the highest-yield parts of Software Engineering. Examiners love it because it is full of crisp, factual distinctions: black-box vs white-box, verification vs validation, the V-model, the levels of testing, test-case design techniques (equivalence partitioning, boundary value analysis), and famous one-liners (Dijkstra's quote, "cost of a bug rises the later it is found"). Almost every question is a definition, a comparison, or a small calculation — exactly the kind you can lock down completely with this lesson.
Learning objectives
- Define software testing, defect/error/fault/failure, and the goal of testing.
- Distinguish verification vs validation and know the V-model.
- Explain the levels of testing: unit, integration, system, acceptance.
- Explain the types/approaches: black-box, white-box, grey-box, and the major static/dynamic distinction.
- Apply test-case design techniques: equivalence partitioning, boundary value analysis, decision tables, state transition.
- Compute cyclomatic complexity and understand basis-path testing and coverage metrics.
- Know functional/non-functional test types: regression, smoke, sanity, performance, load, stress, usability, security.
- Understand the testing process, test artifacts, and where automation fits.
- Avoid the classic exam traps and answer any MCQ or short question on the topic.