Fix empty error message when call is exhausted

[cvgw]

Fixes #404 Description

Fix empty error messages when the received call is exhausted

Submitter Checklist

These are the criteria that every PR should meet, please check them off as you review them:

• [x] Includes tests

Reviewer Notes

• [ ] The code flow looks good.
• [ ] Tests added.

Release Notes

Describe any changes here so maintainer can include it in the release notes, or delete this block.

Fix empty error message when expected method has been called too many times

[cvgw]

PTAL