Let me know if it works for you. I have 12 plus years of experience in IT with various skills sets. I'm good at writing unit test cases, especially for Spring. For an example if the service have email and date of birth as input, i would end up having below scenarios.
1. email is empty, date of birth is present,
2. Email is present, but, date of birth is empty
3. Email is invalid, date of birth is invalid
4. Email is valid, date of birth is invalid
5. Email is valid, date of birth is valid
6. email is valid but date of birth is missing
7. Email is empty, date of birth is valid.