Refactored FileServiceTests.  Added checks for some headers that are required for specific status-codes.
Refactored FileServiceTests.  Added checks for some headers that are required for specific status-codes.

acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core,acmorrow/pion-core