If you set up a patron authentication technique with no test password, it becomes impossible to create a LibraryAuthenticator object for that technique. Some bit of code in the LibraryAuthenticator won't run if the authentication technique has no test password.

I believe this was introduced when we brought in the self-test code, and I think this needs to be fixed before the next release, to avoid problems with people who have the server deployed.

It's probably best to change the code that assumes the test password is required, and actually make the test password be optional once more. That is, change it to treat a missing test password the same as if test password was the entry string. This will avoid migration problems – plus some patron authentication techniques don't use a password at all.