Your example will fail the "Overlapping permutations" test and "Runs test" from the diehard tests. I don't think it's really meaningful to point out that a bad

Your example will fail the "Overlapping permutations" test and "Runs test" from the diehard tests. I don't think it's really meaningful to point out that a bad RNG will pass many of the constituent tests of a particular test battery (e.g. diehard), because each constituent test is generally looking for one particular property.