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Test Design

Black-Box Testing

Testing based on requirements and specifications without knowledge of internal code structure.

Full definition

Black-box testing (also called specification-based testing) evaluates software behavior based on requirements and specifications, without examining internal code. The tester sees the system as a 'black box' — inputs go in, outputs come out, and the internal logic is invisible.

Black-box test design techniques:

  • Equivalence Partitioning
  • Boundary Value Analysis
  • Decision Table Testing
  • State Transition Testing
  • Use Case Testing

Advantages:

  • No programming knowledge required
  • Tests from the user's perspective
  • Independent of implementation — tests remain valid if code is refactored

Limitations:

  • Can miss code-level issues (dead code, unused paths)
  • May have redundant tests without knowing the code structure
  • Hard to achieve complete code coverage

Most manual QA testing is black-box. It's the foundation of functional testing and the starting point for any tester's career.

Learn more about black-box testing in practice

ISTQB track