> If you agree on that, now imagine that you added another project to the fixtures. Has the testing power of the tests changed just because fixtures have been changed?
No, _but_ (and this is a big _but_) you're not testing the contract of the method, which (presumably) is to return all and only active projects.
Testing that it returns _some_ of the active methods is useful, but there are cases where it won't point out an issue. For example, image
- Over time, more tests are added "elsewhere" that use the same fixtures
- More active projects are added to the fixture to support those tests
- The implementation in the method is changed to be faster, and an off-by-one error is introduced; so the last project in the list isn't returned
In that ^ case, testing that _some_ of the active projects are returned will still return true; the bug won't be noticed.
Not directly related to the above, but I'll note that I would also split 2/3 into different tests.
- Make sure all projects returned are active
- Make sure projects returned includes all active projects
I think that's more of a style thing, but I _try_ to stick to each test testing one and only one thing. I don't always do that, but it's a rule of thumb for me.
No, _but_ (and this is a big _but_) you're not testing the contract of the method, which (presumably) is to return all and only active projects.
Testing that it returns _some_ of the active methods is useful, but there are cases where it won't point out an issue. For example, image
- Over time, more tests are added "elsewhere" that use the same fixtures
- More active projects are added to the fixture to support those tests
- The implementation in the method is changed to be faster, and an off-by-one error is introduced; so the last project in the list isn't returned
In that ^ case, testing that _some_ of the active projects are returned will still return true; the bug won't be noticed.
Not directly related to the above, but I'll note that I would also split 2/3 into different tests.
- Make sure all projects returned are active
- Make sure projects returned includes all active projects
I think that's more of a style thing, but I _try_ to stick to each test testing one and only one thing. I don't always do that, but it's a rule of thumb for me.