Add unit tests for DNSQueryMonitoringProtocol

Authored by ema on Mar 20 2017, 12:13 PM.

Description

Add unit tests for DNSQueryMonitoringProtocol

This commit adds unit tests for DNSQueryMonitoringProtocol and
introduces a new method, getQueryDeferred(), that returns the deferred
DNS query used by check() allowing to test its behavior.

Change-Id: I08ad45f6353cdaaac2cc7e9d61bc7302436a3c7f