Spurious error message when using named tests

[jimk-bdrc]

Describe the bug
audit-tool prints an error message when the list of named tests contains a blank entry

To Reproduce

❯ audit-tool -T NoFoldersInImageGroups:NoFilesInFolder::ImageFileNameFormat  /bladd/bla/someplace

prints

WARN  Requested test  not found in test library
ERROR Failed    /bladd/bla/someplace            Image file name format test
ERROR Failed    /bladd/bla/someplace            No Files in Root Folder
ERROR Failed    /bladd/bla/someplace            No folders allowed in Image Group folders

Expected behavior
There was no badly named test in the command line. When the command line's substring :: was changed to : the message was not printed:

❯ audit-tool -T NoFoldersInImageGroups:NoFilesInFolder:ImageFileNameFormat  /bladd/bla/someplace
ERROR Failed    /bladd/bla/someplace            Image file name format test
ERROR Failed    /bladd/bla/someplace            No Files in Root Folder
ERROR Failed    /bladd/bla/someplace            No folders allowed in Image Group folders