Example Model

The following is a simplified example of a model built to test a log-in page’s authentication. Users must enter a valid user name and password, and then they should be authenticated. Any other combination of valid or invalid user name and password should lead to the user not being authenticated.

In terms of cause-and-effect, IF-THEN logic discussed above, this model presents the following paths between the start and possible end points:

1. IF(user enters a valid username AND a valid password), THEN user is valid and Authenticated.
2. IF(user enters an invalid username AND a valid password), THEN user is invalid and is not Authenticated.
3. IF(user enters an invalid username AND a invalid password), THEN user is invalid and is not Authenticated.
4. IF(user enters an valid username AND a invalid password), THEN user is invalid and is not Authenticated.

These paths are equivalent to test cases. They can be represented in the following decision table: