It's just too easy to test the legal envelope without any repercussions. Don't like the limits on your power that the Constitution has in place? Pass the law you want anyway and see if anyone notices. Fake-it-till-you-make-it. The Constitution means whatever fantasy Congress and the President says it means, redefined words and all. In order for The People to be secure, the people need to have their personal security violated. In order for Freedom to live on, freedom must be curtailed. It's not until the Supreme Court has someone shove it in their face too hard for them to ignore it that anyone even starts to look at the provisions of these bills. And then the same guys who passed the first one just try again, often with nearly identical wording to the last time, until everyone is just too damned tired to keep fighting.
Let's create an Amendment to hold congresscritters accountable--say, with jail time--for passing laws that violate the Constitution. The Constitution is law with most of its provisions lacking codified punishments. I think only Treason is defined with an explicit punishment in the Constitution. If the Supreme Court decides a law gets struck down because it is unconstitutional, then all the names on the list of sponsors for the bill go to jail. The Amendment could be that all new Amendments must have a codified punishment and all previous Amendments need to have punishments amended to them.
Stop Cowboy Government.
"Test-driven" means we decide what it should do, then we write the corresponding code.
A "test-driven" nation would decide first what the government ought to do, then proceed by writing the corresponding laws.
The system you describe is the exact opposite: let's write some code / law and then see what happens. You have a Cowboy Congress.
You might amend your last sentence to read "Start Test Driven Government" instead.