tests failing cause a package was not installed, but the package is installed?

I'm working on a repo that has about 236 tests, after running the tests, they all seem to be failing since there's a package that was not installed. I checked on the root folder with pip list, and the required package is installed. So i'm not understanding what's the problem. The package is something that was built here and I installed it in the root directory with the .whl extension.