The is a simple example of how rules about eligibility for unemployment benefits can be modeled.
Here are the rules:
An applicant is ineligible if they voluntarily left work
An applicant is ineligible if they were discharged for misconduct
An applicant is ineligible if they refused to accept work
An applicant is eligible if they have a claim, have registered, are available for work and have served the waiting period
Can you spot the ambiguities and incompleteness in these?
This example also includes an example of how to do automatic regression testing