t/
  other.t
  something.t
  win32/
       ui.t

prove                   t/*.t
prove -r                recursively
prove t/something.t     t/something.t
prove t/win32           t/win32/*.t

If our test suite was setup as outlined above, even without a real perl module, we can also keep the test files in a directory hierarchy under t/ - in that case we have to indicate this in Makefile.PL or Build.PL. We can also run the tests script one-by-one or per directory using the "prove" utility.

Let's see the layout of the sample CPAN packages we have, and run their tests:

By default "make test" or "perl Build test" will run all the t/*.t files. Sometimes we want to run them one by one. We could run perl t/something.t but that would try to use the installed versions of the modules you are using and not those you are about to install. So better use perl -Ilib t/something.t for that.

Even better to use the prove t/something.t command that comes with Test::More. It too by default would attempt to use the already installed modules so you could run prove -b t/something.t to include the files from blib/lib. Prove has another frequently used flag: -v which puts it in verbose mode.