Do I need to write all intended properties before I start the Fuzzer

No, you can choose if you want to check for one property at a time or rather check multiple properties at the same time. You can run several Fuzzing campaigns.

Important:

• More is not necessarily better! Reflect on which properties are important.

• Start with two or three simple properties just to get started. Make sure to add a property that should not hold. This allows you to verify if the fuzzer is set up correctly.

• You can always add more properties, just like you can always add more unit tests.