test(proxy): partition related endpoints tested

This patch also introduces a base class to test proxy.

Change-Id: I7693f326f783fd860bec38c3f5ae56b4ec614128
test(proxy): catalog tested

Change-Id: I7418f330439a5771d7baba6734c8f94b0d8ceb3a
Merge "test(proxy): partition related endpoints tested"
Merge "test(proxy): catalog tested"