Code Contract Assertions

A set of extension methods for making runtime assertions that can help to catch code contract violations.

void AddUserToDatabase(User user)
{
    // Check that the user is not null and that the age is greater than 18.
    user.ContractAssertNotNull();
    user.Age.ContractAssert(p => p > 18, "Age must be greater than 18");
}

Any assertion failure will result in a ContractViolationException being thrown. It is recommended not to catch these exceptions, but to let them bubble up to the application root where they can be logged and the application terminated cleanly. A ContractViolationException is an unequivocal indication of a bug in the code, so it should never be caught and handled. It is a failure of the code contract, not a runtime error that can be recovered from.