We used to install the package in our
functional tests with editable installs, but
as also mentioned in https://pip.pypa.io/en/stable/topics/local-project-installs/#regular-installs:

> This will install the project into the Python that pip is associated with,
in a manner similar to how it would actually be installed.
This is what should be used in CI system and for deployments, since it most
closely mirrors how a package would get installed if you build a distribution
and installed from it...