'Test::Harness' assumes that you want to run all of the .t files in the
t/ directory in ASCII-betical order during 'make test' or './Build test'
unless you say otherwise. This leads to some interesting naming schemes for
test files to get them in the desired order. These interesting names ossify
when they get into source control, and get even more interesting as more
tests show up.
'Test::Manifest' overrides the default test file order. Instead of running
all of the t/*.t files in ASCII-betical order, it looks in the
t/test_manifest file to find out which tests you want to run and the
order in which you want to run them. It constructs the right value for the
build system to do the right thing.
In t/test_manifest, simply list the tests that you want to run. Their
order in the file is the order in which they run. You can comment lines
with a '#', just like in Perl, and 'Test::Manifest' will strip leading and
trailing whitespace from each line. It also checks that the specified file
is actually in the t/ directory. If the file does not exist, it does not
put its name in the list of test files to run and it will issue a warning.
Optionally, you can add a number after the test name in test_manifest to
define sets of tests. See 'get_t_files' for more information.