anchor.diff:  |===
   |Action   |Result   
   //-------------
  -|Create a subscription on `2021-09-10`   |Invoice generated for `$24.95` for `2021-09-10` to `2021-10-10` 
  +|Create a subscription on `2021-09-10` (current date)  |Invoice generated for `$24.95` for `2021-09-10` to `2021-10-10` 
   |Trigger invoice dry run with target date `2021-09-18`    |Invoice generated for  `$24.95` for `2021-09-17` to `2021-09-24`  
   |Trigger invoice dry run with target date `2021-10-15`    |Invoice generated for  `$24.95` for `2021-10-15` to `2021-10-22`   
   |Trigger invoice dry run with target date `2021-10-29`    |No invoice generated as the fixed term is over.  
  
positive.code: |Action   |Result   
  //-------------
  |Create a new account. Leave BCD field empty  |Account created, BCD is blank.
  |Create a subscription on `2021-09-17`   |Invoice generated for `$24.95` for `2021-09-17` to `2021-10-17`. BCD set to `17` (Since subscription is created on 17th)
  |Create a subscription, with date as `2021-09-25`   |No invoice generated
  |Trigger invoice dry run with target date `2021-09-25`   |Invoice generated for `$18.30` for `2021-09-25` to `2021-10-17` (Prorated since BCD is 17)
  |Trigger invoice dry run with target date `2021-10-17`   |Invoice generated with two invoice items corresponding to both subscriptions for `$49.90`. 
  |===
  
negative.code: |===
  |Action   |Result   
  //-------------
  |Create a subscription on `2021-09-10` (current date)  |Invoice generated for `$0` due to trial phase
  |Trigger invoice dry run with target date `2021-09-20`    |Trial phase ends so Invoice generated for `$24.95` for `2021-09-20` to `2021-10-20`  
  |Trigger invoice dry run with target date `2021-10-20`    |Invoice generated for  `$24.95` for `2021-10-20` to `2022-11-20`   
  |Trigger invoice dry run with target date `2022-01-20`    |Invoice generated for  `$24.95` for `2022-01-20` to `2022-02-20` 
  