The "Unit" in "Unit Test" is the Test!

"The Unit of isolation is the Test."

Patryk Kocielnik

Writing with the hope that a record of the random things people do around can save some duplication of effort -- except for fun.

More posts by Patryk Kocielnik.

Patryk Kocielnik

13 Nov 2024 • 1 min read

A lot of mistakes has been made, because people think the "unit of isolation" is the class under test.

It is not.

(...)

The unit of isolation is the test – not the thing under test.

– Ian Cooper, "TDD, Where Did It All Go Wrong", https://youtu.be/EZ05e7EMOLM?t=2121

When you treat every test as a "unit", meaning a complete example, you force yourself to design your program in such a way, that each of your features is very easily accessible.

That is because you make yourself the first person to feel the pain of setting the whole thing up before it is ready to do something of value to the user.