Increase edp module test coverage
Increase edp module test coverage

Write unittests for edp.hdfs_helper from scratch.

Change-Id: If4746620655827b4f43944baf66991b07f02a44d

esikachev/sahara-backup,ekasitk/sahara,esikachev/sahara-backup,zhangjunli177/sahara,ekasitk/sahara,egafford/sahara,zhangjunli177/sahara,tellesnobrega/sahara,crobby/sahara,egafford/sahara,zhangjunli177/sahara,crobby/sahara,openstack/sahara,crobby/sahara,ekasitk/sahara,openstack/sahara,tellesnobrega/sahara,esikachev/sahara-backup