How to run 2 different sites using the same containers?

[VladSavitsky]

Describe your issue

Currently I have one site running without problems but I want to have other installation (to tests only). I want them run at the same time but can't figure out how to configure this. They must have separate code base and database but could share the same docker containers. Problem is that when I run tests I can't change codebase (switch to other branch or change files) so tests block my work now.