Make unit tests more precise
Make unit tests more precise

* Don't assume implementation or type of Config.event_log
* expect ahead of time rather than allowing and then expecting

[#139870257](https://www.pivotaltracker.com/story/show/139870257)

Signed-off-by: Joshua Aresty <18e47c05d12d69c65baf02b69e877c81d203331d@emc.com>

barthy1/bosh,barthy1/bosh,barthy1/bosh,barthy1/bosh