Fix #1487: Reduced test case

[chrisbreiding]

This is a modification of #1490 that addresses issues raised by @fatso83.

[fatso83]

Great stuff. Could you remove the conflict with the master branch as well, and just amend the last commit?

[coveralls]

Coverage increased (+0.005%) to 95.522% when pulling b7ce6dd on cypress-io:issues/#1487 into cbf1128 on sinonjs:master.

[chrisbreiding]

I rebased master. Not sure if that's exactly what you had in mind, but it fixed the conflict.

[fatso83]

Thanks!