If you've ever tried to use Test::NoWarnings to confirm there are no warnings
generated by your tests, combined with the convenience of done_testing to not
have to declare a test count, you'll have discovered that these two features do
not play well together, as the test count will be calculated before the warnings
test is run, resulting in a TAP error. (See examples/test_nowarnings.pl in this
distribution for a demonstration.)

This module is intended to be used as a drop-in replacement for
Test::NoWarnings: it also adds an extra test, but runs this test before
done_testing calculates the test count, rather than after. It does this by
hooking into done_testing as well as via an END block. You can declare a plan,
or not, and things will still Just Work.