A lot of projects include a "check" target in their makefiles. Right now, we don't use these checks and just upload a package after compiling it, sometimes even without a runtime test. I would propose to add checks to important packages. Examples include glibc, glib2, cairo, MySQL, Mozilla stuff and more. Running make check can result in better package quality. Upstream usually runs these tests before releasing, but they don't test every possible combinations of packages that a distribution ships. To implement this, I would propose to have some kind of check function inside the PKGBUILD, which can be called by makepkg if "check" is in the options array. Other option is to include make check inside the build() function, but that will make it non-optional. This package checking stuff could get implemented in an automatic build bot in the future. Not only will that build bot detect packages which don't build anymore, but it will also detect regressions caused by package updates. A package like xulrunner or firefox could pass the check without errors on package upload, but it could break after updating cairo or gtk2 for example.