The shell parameter expansion using # and ## is not supported in
Solaris 10 Bourne shell (/bin/sh). Even though this is POSIX, it is not fully
portable, so we should avoid it.
If a command line argument is given, then only the test file
of that type is created. It's quite dumb in sense that unknown
names don't give an error but it's good enough here.
Also use EXIT_FAILURE instead of 1 as exit status for errors.
