Testing Strategies

This lesson covers software testing strategies — the systematic approaches used to verify that software works correctly, meets requirements, and is free from defects. Testing is a critical part of the software development lifecycle and a key topic in A-Level Computer Science.

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Why Test Software?

Testing is essential because:

• It identifies bugs and defects before the software reaches users.
• It verifies that the software meets its requirements.
• It ensures the software is reliable, secure, and performant.
• It reduces the cost of fixing errors — bugs found early are cheaper to fix.
• It builds confidence that the software works as expected.

Exam Tip: You should know the difference between verification (checking the software is built correctly — "are we building the product right?") and validation (checking the right software is built — "are we building the right product?"). Testing contributes to both.

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Types of Testing

Unit Testing

Unit testing tests individual components (functions, methods, or classes) in isolation from the rest of the system. Each test checks that a single "unit" of code produces the correct output for a given input.