The cause is easy: the people specifying the problem to be solved don't ask for an independent set of tests that are human-readable and can be run automatically to verify the system.
If they did that, then the system would be verifiable and so would changes to it - the tests would simply need to be adapted to talk to the new version of the system.
Too late now, of course. But that's what should be done.
If they did that, then the system would be verifiable and so would changes to it - the tests would simply need to be adapted to talk to the new version of the system.
Too late now, of course. But that's what should be done.