Hi @Peter,
Thanks for asking this question here! 
Did you register the project in the last couple of weeks? Iâm asking because we now have a scanner for macOS projects New project scanner which should auto configure a workflow for you if it detects your repo as a macOS project.
If thatâs an option it might be the best to register the repo again, and let the bitrise scanner prepare it for you.
If youâd want to do this manually
You can use the Xcode Test for Mac step - but if you registered the repository before the macOS scanner, this step might not be in the default list when you click the âadd new stepâ + icon in the workflow editor.
If that would be the case, you should go to the Settings tab of the app, and change the project type to MacOS in the Project Type Selector
After this you should see the Xcode Test for Mac step in the step list.
An alternative solution is to turn off the Filter by platform option in the step list popup
When this filter is turned off all available steps are listed, but be careful as there might be steps which are not compatible with your macOS project.
If youâd have any questions just let us know!