Helix JobSender unit tests for payloads

[jonfortescue]

• This issue is blocking
• This issue is causing unreasonable pain

We have a lot of expected functionality around payloads, e.g. by default directory payloads zip up the contents of the directory, but can optionally include the directory itself as the top level entry in the zip. We need to validate that all of the expected behaviors around these work.

[missymessa]

Need to flesh this out with a comprehensive test plan for what behaviors need to be tested. Tagging a couple folks for input on what code paths should be tested.

/cc @MattGal @alexperovich @ChadNedzlek

[ChadNedzlek]

• For DirectoryPayload
  • Long paths
  • With trailing slash
  • Absolute and relative paths
  • Directories that have unicode characters
  • Directories with files with unicode characters
  • Files with no extensions
  • Files with only extensions
  • Hidden files
  • Directory junctions
  • Symbolic links
  • Symbolic links that cause cycles (A/B/linkToA)
  • Errors states
    • Invalid file characters
    • Files that don't have permissions (check error states)
    • Files that are locked for reading
    • Target file already exists
    • Directory doesn't exist
  • All that again, but for "ArchiveEntryPrefix" (based on the reading, I bet this is going to do bad things the tests will uncover... there is very little validation around this value)
  • Caching
    • Uncached
    • Cached
    • Expired cache