Indeed. The output of a noncryptographic generator like the Mersenne Twister would also pass those same tests, and would be not secure at all. This is not how i

Indeed. The output of a noncryptographic generator like the Mersenne Twister would also pass those same tests, and would be not secure at all. This is not how indistinguishability works. The 'correct' to make this point would be to analyze the volume format, and reduce distinguishing the container to distinguishing the underlying block cipher from a pseudorandom permutation. That is, distinguishing a TC volume implies distinguishing AES (or whichever block cipher combo TC supports).