Trying to emerge dev-libs/glib-2.28.6 with tests enabled requires xorg-server[xvfb]. This makes it impossible to emerge with xorg-server[-xvfb] or, specially, on a system without X11. I don't know if this should really be considered an issue, but I like to run some of my test/devel box with FEATURES=test but some of them are headless remote systems without X11 installed and I find it annoying having to install some 51 new packages just to run the test suite of glib. If it is considered standard behavior to require Xorg[xvfb] to run glib's test suite, then please close this bug. If someone thinks it could be a good idea to run tests without Xorg, it should be handled in the ebuild, possibly disabling some of the tests where X11 is actually required.
We need Xmake for running tests as explained in ebuild and, then, this dependency is inheritted from virtualx.eclass
