Obviously I should be semantically careful: "job" and "author" are overloaded words. How about this:

It's a general expectation among users of Perl that module maintainers are interested in maintaining their modules, and that said maintainers will try their best to remove any failing tests (that are under their power to do so).

The parenthetical bit at the end is in response to the broken-CPAN straw man argument. Obviously (rare) things like that are out of control of the author, along with bugs in any other dependencies, OS utility, etc.

I recognize that CPAN is a volunteer effort, but it does seem to me there is a implicit responsibility on the part of the author to maintain the module going forward, or to pass the baton to someone else. Call it a Best Practice, if you will. The end-user simply wants the module to work. Maintainers not paying attention, and the subsequent bitrot that is appearing on CPAN, is one of Perl's biggest problems at the moment. Careful attention and responsiveness to CPAN testers and to rt.cpan.org is the best cure for this.