To test a testing module, you must use a test tester. With a little help from you, they learn how to understand what is the output of your testing module and what's a test for real. You have at least two:

• Test::Builder::Tester (which will be part of the core in 5.10 and is already shipped with the Test-Simple distribution)
• Test::Tester by Fergal Daly

I don't have any experience with the last one, but I may say that using Test::Builder::Tester seems awkward to me, but maybe it is just as it must be for a weird task like testing a test.