Define Test Scenario:

Test scenario is a thread of operational use at any level of testing.

1. At system level , the operational use is one such use/abuse by the end customer
2. Scenarios are long at system level and short at unit test level.

Example ;Login screen

TS1 : Ensure that an invalid user is disallowed tobe logged in

1. tc1: invalid name - Name is null
2. tc2: name is too long
3. tc3: name contains illegal character
4. tc4: name is not a registered user name.