Sequence Enumeration: Use Case 2


Precondition:
Machine is ON and there is one soda in the machine.

Description:
User walks up to machine and puts 2 quarters in. 
He then presses the soda button. 
Nothing comes out as 3 quarters are needed to get a soda.
The user presses the change button and retrieves his change.
User leaves to obtain another quarter.
User returns, enters 3 quarters and selects a soda.
Soda is delivered.
The "sold out" light is turned on as this was the last soda in the drinks hopper.