Test Patterns
Test Driven Development
Principles
Write tests first
- Writing your tests first helps to prevent over-engineering a solution and provides a suite or regression tests to prevent breaking existing functionality.
Refactoring
- “The freedom to refactor with impunity is made possible by unit testing. Together, unit testing and refactoring form a mutually beneficial relationship, whereby unit testing enables refactoring and refactoring improves the design of code” - Gary McLean Hall (1)
TDD
- Development driven by tests producing just enough design.
- Overengineering occurs when code is made pointlessly adaptive - that is, it can be extended in ways that it will never need.
- Without becoming a domain expert in the field, you need a design tool that will guide you through the process of capturing labyrinthine requirements in working, verified code.
- Class, responsability, and collaboration (CSC) design sessions.
Testing pyramid
\ Manual tests
\ \ Acceptance tests (UI automation)
\ \ \ Integration tests (black box)
\ \ \ \ Unit tests
Hourglass - When it has too many integration and acceptance tests, code is difficult to change.
Snowcone - When the majority of testing effort is manual, this indicates that you have an untestable codebase.
Testing Quadrant (Gojko Adzic)
Patterns
Builder pattern
- Clarifies unit test intent, functional domain-specific language (DSL)
- Reduces repetitive setup code
Reference:
McLean, H. G. (2017). Adaptive Code: Agile coding with design patterns and SOLID principles, 2nd Edition. Microsoft Press