We currently do this in the test suite:

    @test GAP.Packages.install("io", interactive = false)
    @test GAP.Packages.remove("io", interactive = false)

... which is inconvenient as it means that after running the test suite, the IO package is removed...

Better would be to reactivate the commented out variant coming afterwards:

#    pkgdir = mktempdir()
#    @test GAP.Packages.install("io", interactive = false, pkgdir = pkgdir)
#    @test GAP.Packages.remove("io", interactive = false, pkgdir = pkgdir)

I think this fails because the installed package can not be actually loaded; so to "fix" this, one probably needs to add the temporary pkgdir to the list of directories GAP searches for packages, e.g. via ExtendRootDirectories