There are a lot of PRNG test batteries, like DieHarder. They do check that some statistical tests expected for random sequence are indeed present.
But is there any theoretical motivation, why this should work? Why all other statistical tests would probably work too? And why PRNG would be good in crypto way, meaning that it could not be predicted?
By this answer it appears like currently non-relative proofs of PRNG security are not available at all, but maybe there are at least justifications why some statistical tests are "better" (i.e. generating all others)?
This seems similar to definition of randomness in algorithmic randomness theory, but I am not sure if there is a direct link.