TODO Verbose output
$ prove -lv t/34.t
# Add two numbers # Add 3 numbers t/34.t .. 1..3 ok 1 - 1+1 ok 2 - 2+2 not ok 3 - 2+2+2 # TODO fix bug summing more than 2 values #173 # Failed (TODO) test '2+2+2' # at t/34.t line 16. # got: '4' # expected: '6' ok All tests successful. Files=1, Tests=3, 0 wallclock secs ( 0.01 usr 0.00 sys + 0.03 cusr 0.00 csys = 0.04 CPU) Result: PASS
Of course after you already wrote your tests for a new feature but before you can write the actual code there is a short time period when your test suit will not pass 100%.
Worse than that, it is also recommended that immediately when you get a bug report from somewhere you should write a test case that reproduces this bug. Obviously this test will fail before you fix the bug and will hopefully pass once you fixed it.
In order to make the test suit happy there is a way to tell the harness tool that a test is *supposed to fail*. That is, we know it will fail. What we can do to achieve this is to set one or more tests to be in a TODO block.