What is the ruling on a husband uttering divorce pronouncements in cases of doubt, such as: self-talk, or uttering them while asleep, or when in doubt about whether divorce has occurred or not, or uttering them with the intention of testing how the pronouncement is uttered? And what is the ruling on taking back one's wife when in doubt about the divorce? Is it a condition that the divorce pronouncement be audible?

The Fatwa (definition)'s Conclusion:

What you are experiencing is severe obsessive-compulsive disorder (waswasah) concerning divorce, which has no effect on your marital life. This is because the marriage contract is only dissolved by a matter of certainty, such as divorce or khula (definition), and certainty is not removed by doubt. As long as you doubt whether you uttered the words of divorce, or you did not intend divorce with one of its allusive phrases, none of this is taken into consideration. It does not appear from your question that you have divorced your wife.