test a Mac app to see if it has everything it needs packaged

One way would be to remove all homebrew packages, which would not be recommended - apparently this can be done like

brew remove --force $(brew list --formula) --ignore-dependencies

(not tested)

But an easier way is to just rename the homebrew directory, for eg on Apple Silicon Macs,

sudo mv /opt/homebrew /opt/homebrew-backup

(and after finishing the tests, rename it back.)