anchor.diff:  
   It is important to understand that the *Payment Retry System* and the *Overdue system* are *independent* of each other. So, the *Payment Retry System* attempts payments as per its retry schedule while the *overdue system* moves the account from one state to the other as per its configuration.
   
  -Having said that, most business cases would require using both the systems in conjunction with one another. This is because most business cases would prefer to retry payments several times before blocking the user's access.
  +Having said that, most business cases would require to retry payments several times before blocking the user's access and thus would require using both systems in conjunction with one another. 
   
   Although the payment retry system and overdue systems need to be configured independently of each other, it makes sense to *align payment retries with overdue states*. This allows retrying the payment on the boundary of each overdue state and thus prevents transitioning from one state to the next if the payment gets retried successfully. Further, to ensure that the payment is always retried before the overdue system, it makes sense to configure a payment retry 1 day before each overdue state. 
   
  
positive.code: 
  image:https://github.com/killbill/killbill-docs/raw/v3/userguide/assets/img/overdue/overdue-flow4.png[align=center]
  
  As in the case of the previous flow, the payment retry system retries the payment two times on `2021-08-07` and on `2021-08-15`. The Overdue flow then kicks in and moves the account to the `WARNING` state on `2021-08-16`. The payment retry system makes the the third payment attempt on `2021-08-19` which fails. The Overdue system (which is configured to run *4* days after the previous run) runs on `2021-08-20` and moves the account to the `BLOCKED` state. Since the customer does not fix the payment issue, the payment fails when the payment retry system attempt it the fourth time on `2021-08-26`. The Overdue system is configured to run one more time after *7* day after the previous run. Since the Overdue system was previously run on `2021-08-20`, it runs on `2021-08-27` and moves the account to the `CANCELLATION` state. 
  
  [[testing]]
  == Configuring the Payment Test Plugin
  
negative.code: 
  Before we dive into the details, let us understand some high-level concepts.
  
  Kill Bill has two distinct built-in mechanisms. These are the *Payment Retry System* and the *Overdue System*. Though separate, these two systems work in close conjunction with each other.
  
  The *Payment Retry System* is a system that retries failed payments as per a defined schedule. The schedule can be defined via a property in the Kill Bill configuration file or can be uploaded on a per-tenant basis.
  
  