Learn something new every day.
- I am a senior software engineer working in industry, teaching and writing on software design, SOLID principles, DDD and TDD.
Location
Buenos Aires
Education
Computer Science Degree at Universidad de Buenos Aires
I agree with you testability is one of the most important quality attributes of a system.
Test doubles decrease the confidence of a system since you are not testing a real one.
If you need to isolate your system you can build an interface and have two implementations: one for real and one for testing. Therefore you don't have just one realization. You have two. And you are no longer in code smell scenario
That said. Your last paragraph is the most important
Learn something new every day.
- I am a senior software engineer working in industry, teaching and writing on software design, SOLID principles, DDD and TDD.
Location
Buenos Aires
Education
Computer Science Degree at Universidad de Buenos Aires
Interfaces for external dependencies allow you the flexibility of using either a test double or a real implementation without much overhead. Arguing about that is a moot point.
There is a lot to be said about levels and granularity of testing but that's not this post!
Learn something new every day.
- I am a senior software engineer working in industry, teaching and writing on software design, SOLID principles, DDD and TDD.
Location
Buenos Aires
Education
Computer Science Degree at Universidad de Buenos Aires
I agree with you testability is one of the most important quality attributes of a system.
Test doubles decrease the confidence of a system since you are not testing a real one.
If you need to isolate your system you can build an interface and have two implementations: one for real and one for testing. Therefore you don't have just one realization. You have two. And you are no longer in code smell scenario
That said. Your last paragraph is the most important
How is creating an implementation for testing, not a test double?
You need to use real objects for testing, not mock or test objects
Interfaces for external dependencies allow you the flexibility of using either a test double or a real implementation without much overhead. Arguing about that is a moot point.
There is a lot to be said about levels and granularity of testing but that's not this post!
Right! there also a lot of test smells, many on this series and many others to come!