Question 3: Test of the class Purchase

Bill number: 1000, date: 1
Client: Larry O'Brien, email: larry@obrien.ca
Items ordered:
   * Garfield (Book)
Total: $0
Remaning credit for Larry O'Brien : 2$
There is 1 copies of Garfield available

Bill number: 1001, date: 1
Client: Larry O'Brien, email: larry@obrien.ca
Items ordered:
   * Da Vinci Code (Book)
   * Garfield (Book)
   * HALO 2 (Video game)
Total: $55

There are 0 copies available Garfield
Bill #1001, cost: 55$, purchased on day: 1
Remaining credit for Larry O'Brien : 0$

Bill number: 1002, date: 2
Client: Grace Hopper, email: grace@coldmail.org
Items ordered:
   * Harry Potter III (DVD)
   * Schindler's List (DVD)
   * HALO 2 (Video game)
Total: $65

Error: No copy of 'Garfield' is available.
Bill number: 1003, date: 4
Client: Larry O'Brien, email: larry@obrien.ca
Items ordered:
   * Harry Potter III (DVD)
   * Garfield (Book)
Total: $18

Harry Potter III purchased in purchase0? false
Harry Potter III purchased in purchase1? false
Harry Potter III purchased in purchase2? true
Harry Potter III purchased in purchase3? true

Error: No copy of 'HALO 2' is available.
Bill number: 1004, date: 8
Client: Larry O'Brien, email: larry@obrien.ca
Items ordered:
   * HALO 2 (Video game)
Total: $0

Credit for Larry O'Brien: 0