Refactor existing endpoint filter tests

Refactored the existing suite of endpoint filter tests including
renaming method names to aid readability and added additional
comments.

Change-Id: I98ded2632a6130e2b664e987f08499162801be6b
Surround REMOTE_USER variable name with quotes.

REMOTE_USER should be surrounded with `` signs to follow RST rules.

Change-Id: I2c0ba8abff7950087a7828f30208292e66d8aaf8
Merge "Surround REMOTE_USER variable name with quotes."
Merge "Refactor existing endpoint filter tests"
Remove unused function

_assertNotifySeen was not being called.

Change-Id: I1f76aede7d1d3e6092c8e2bafa4af6c5eb5b74a3