Its better to use the variables that have been created in the base class. The reason being if in future we have to change something in how the FS object is being created its done in one class the base class and all the children classes dont need to be updated. For example if we decide to add a config to the fs object etc. There could be other examples as well but i dont want to hold up the merge for this.

But as a practice i would like all tests to use oozie client, FS objects from the base class.