testbinaries 'substract from a arch-set' 'i386'
echo 'deb [arch=mips,i386 arch-=mips] http://example.org/debian stable rocks' > rootdir/etc/apt/sources.list
-testbinaries 'useless substract from a arch-set' 'i386'
+testbinaries 'useless subtract from a arch-set' 'i386'
echo 'deb [arch=mips,i386 arch+=armhf] http://example.org/debian stable rocks' > rootdir/etc/apt/sources.list
testbinaries 'addition to a arch-set' 'i386' 'mips' 'armhf'