Client validation does not provide invalid job context in error messages

[mperham]

Sidekiq::Client#normalize_item runs several validations on the job payload and raises an error if the job format is incorrect but it does not show the incorrect job payload so the developer does not have the context necessary to quickly narrow down the source of the error. Example:

raise(ArgumentError, "Job must be a Hash with 'class' and 'args' keys: { 'class' => SomeWorker, 'args' => ['bob', 1, :foo => 'bar'] }") unless item.is_a?(Hash) ...

Does not actually include item in the error message...