There are some important points:
There are some important guidelines
The extend relationship provides an answer. The idea is to create an extending or addition use case, and within it, describe where and under what condition it extends the behavior of some base use case.
Factor out sub function use cases and use the include relationship when:
There are nine main Steps:
Actor: Something with behavior e.g. Person, Computer System, cashier etc.
Actors are divided into the following categories:
There are type of tests for use case: