Fifth testing technique is use case testing

Use Case describes interactions between users and systems.

Test Cases delivered from use case are useful in under covering defects in process flow during real world use of system.

A use case usually has a most likely scenario and alternative path , pre-condition ,post condition and a final state after use case has been completed.

Example of use case where user tries to make a purchase at vending machine using credit card.

Main Scenario-

Pre-condition - User has a credit card and is close to a vending machine

Steps

1.-Insert Card

2.Validate card and ask for pin

3.Enter pin

4.Validate pin

5.Access the account

Post condition - User is able to access his/her credit card account to make a purchase

Alternate Scenario for some of the above steps

2a-Card not valid

4a-Pin not valid

4b-Pin not valid second time