1099771 - Add a unit test to assert correct behavior for reporting inval...

...id checksums.

We had a bug reported against 2.3[0] wherein a module was not being used correctly. It turns out that this was already fixed in 2.4, but there was
still no unit test coverage on the code that caused the exception. This commit adds coverage to that code.

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1099771