Test types
🔲 Black-box Testing
Definition:
Black-box testing is a method of software testing that focuses on what the software does, without any knowledge of the internal code or logic.
Key points:
- The tester only knows the inputs and expected outputs.
- Tests are based on requirements and functionality.
- Common techniques: boundary value analysis, equivalence partitioning, state transition testing.
- Used for system testing, acceptance testing, and often integration testing.
Example:
Testing a login form by entering valid and invalid usernames/passwords to see if the system behaves correctly, without knowing how the authentication is implemented internally.
⚪ White-box Testing
Definition:
White-box testing (also called clear-box or glass-box testing) is a method where the tester has access to the internal code, and tests are based on the internal logic and structure of the code.
Key points:
- The tester uses knowledge of the source code to design test cases.
- Focuses on code paths, conditions, loops, and branches.
- Common techniques: statement coverage, branch coverage, path testing.
- Often used for unit testing and security testing.
Example:
Testing each possible branch of an if statement in a function to make sure every line of code is executed at least once.
Comparison Black vs White testing
| Feature | Black-box Testing | White-box Testing |
|---|---|---|
| Focus | Functionality / behavior | Internal logic / code structure |
| Tester knows code? | ❌ No knowledge of internal code | ✅ Full knowledge of internal code |
| Test basis | Requirements and specifications | Source code, control flow, and logic |
| Typical use | System, integration, and acceptance testing | Unit testing, sometimes integration |
| Test techniques | - Equivalence partitioning - Boundary value analysis - State transition | - Statement coverage - Branch coverage - Path testing |
| Tools | UI test frameworks, API testing tools | Unit test frameworks, static code analyzers |
| Examples | Testing a form submission, login page, or API response | Testing all code paths in a sorting function |
| Best for detecting | Missing or incorrect functionality | Logic errors, unreachable code, security issues |