Hi Liam, After the fix that, supposedly, would let the test assertions fail reproducibly (but didn't), I just now pushed a new version of example.lisp that should fix the remaining problem. At least, it does so on my computer. I consistently get a number of failed assertions that matches the expected amount that should fail, based on the number of stride > 1 cases. If you find that this works, I would very much like you to check the following: 1. The only real change I made was in the function test-fft-noise, in the section that returns the backward vector. Originally, for gsl > 1.12, you did an elt/ on a (copy backward). I replaced this with a vector/length. I don't understand why you did a copy of backward, so I removed that. Is that correct? 2. Since I have NO idea what happens for gsl <= 1.12 and no fsbv, I just did something which seemed right and removed the map. Is this correct? However, while I don't know what does and doesn't work in this case, I suspect that vector/length should work fine also for gsl <= 1.12 and no fsbv, since it loops over the individual elements. I hope this removes the randomness, and we can get down to "real" testing! Regards, Sumant -- Sumant Oemrawsingh soemraws@xs4all.nl