I don't think the problems with Apache::Test and mod_perl are
necessarily related; for one thing, mod_perl 1 doesn't use Apache::Test
(mod_perl 2 does), and also, Apache::Test doesn't require mod_perl.
What were the problems you had with Apache::Test? Were they
also one of permissions? You might try unpacking, building, and
testing all of these packages as some user other than root, only
becoming root to install things; there have been some problems
reported with testing these as root. Also, if you have more than
one httpd on your system (eg, a 1.3 and a 2.0 version), you might
have to tell these packages explicitly which one to use - for example,
for mod_perl 1, specify the right APACHE_SRC Makefile.PL
value, and for Apache::Test, there's a -httpd option when running
the tests to specify the location of the httpd you want.
You might want to take this to the mod_perl mailing list (see
someone there might have encountered a similar problem.