Automated Testing set up for BCsandbox

I am trying to set up an envoirnment to start developing test app for the app I developed.

My app was developed on BC on prem (locally, not a docker container) and since all the resources I found on the internet says to use testtoolkit you need a docker bcsandbox. So I pulled the latest image, created a container (while created added includetesttoolkit) it showed as the command was executing the test libraries and app was being published.

Then I go to my VScode, create a new project, add "test" with the right version no. in app.json and connect to this container instance and try downloading symbols hoping the alpackage folder will have test.app as well. What happens is as I try to download the symbol VScode throws me an error saying it could not find the test.app file in alpackage folder. Yes ofcourse because downloading symbols would bring that file. I don't know what am I doing wrong.