I removed dev-util/cppunit and got
>>> package: dev-util/cppunit-1.12.1
* - /usr/lib64/libcppunit-1.12.so.1
* - /usr/lib64/libcppunit-1.12.so.1.0.0
* used by /usr/bin/dirac_unittest (media-video/dirac-1.0.2)
On my system (x86) cppunit is no longer needed for any other package and was removed by depclean.
* broken /usr/bin/dirac_unittest (requires libcppunit-1.12.so.1)
I re-emerged dirac (without installed cppunit) and the package no longer contains /usr/bin/dirac_unittest.
But as soon as I install cppunit again and re-emerge dirac, /usr/bin/dirac_unittest reappears.
I would fix it this way:
1. dirac should depend (mind: not rdepend) on cpp_unit
2. /usr/bin/dirac_unittest should never be installed