I didn't have an exact contract with my ex, but we worked with a mediator to establish a protocol we would follow in the event that he missed a Sober Link test.
It was useless essentially. In each case he argued why I was abusing the "intent" behind our agreement and how a missed test shouldn't be interpreted that he was drinking etc.
This in spite of the fact that the protocol spelled out specifically: we agree to treat a missed test as if he were drinking.
The protocol was just a way of him getting me off his back and nothing more.
I like the idea of a contract with yourself, however. That would be enforceable!