Factor random_uniform_01 into nondeterministic and deterministic parts, and automatically test the deterministic part
random_uniform_01 code is not automatically tested by any deterministic tests -- it is tested only by the stochastic tests in the slow test suite. However, there is a not-entirely-trivial deterministic computation inside it, wired up to a (truncated) geometric(1/2) sampler and a uniform bit sampler. And it turns out that this deterministic computation technically has a bug, although the bug triggers with probability <2^-900^ so it doesn't really matter. But it is nice to have deterministic tests for correct behaviour of the deterministic part of a random sampler, and nice for that deterministic part to not have bugs.