The specs were verifying that the publish notification did not exist and not that the publish notification was simply marked as processed
Subscribers who reply unsuccessfully will have their content update reposted
Make all active subscriptions valid past the expiration date of the publish notification
Add PublishNotificationExpirationPolicy
Rename PublishNotification#mark_processed to #process
Change PublishNotification's state from being a boolean to a string
Add expirability to Publish Notification
Add a notion of a policy for expiring unsuccessful Publish Notifications
Subscribers who repeatedly reply unsuccessfully will have their notification request revoked after a reasonable period of time
Merge branch 'feature/expire-old-publish-notifications'

* feature/expire-old-publish-notifications:
  Subscribers who repeatedly reply unsuccessfully will have their notification request revoked after a reasonable period of time
  Add a notion of a policy for expiring unsuccessful Publish Notifications
  Add expirability to Publish Notification
  Change PublishNotification's state from being a boolean to a string
  Rename PublishNotification#mark_processed to #process
  Add PublishNotificationExpirationPolicy
  Make all active subscriptions valid past the expiration date of the publish notification
  Subscribers who reply unsuccessfully will have their content update reposted
  The specs were verifying that the publish notification did not exist and not that the publish notification was simply marked as processed
Add a digest header when sending the content if a secret was passed in with the subscription
Pass the digest through when broadcasting content
Add missing require
Whitespace
Merge branch 'feature/add-digest-hash-when-distributing-content'

* feature/add-digest-hash-when-distributing-content:
  Whitespace
  Add missing require
  Pass the digest through when broadcasting content
  Add a digest header when sending the content if a secret was passed in with the subscription