On 27 Jul 2016, at 15:32, Jeff King [off-list ref] wrote:
On Wed, Jul 27, 2016 at 04:35:32AM +0200, Torsten Bögershausen wrote:
quoted
quoted
+ mkdir -p generated-test-data &&
+ for i in $(test_seq 1 $T0021_LARGE_FILE_SIZE)
+ do
+ # Generate 1MB of empty data and 100 bytes of random characters
+ printf "%1048576d" 1
+ printf "$(LC_ALL=C tr -dc "A-Za-z0-9" </dev/urandom | dd bs=$((RANDOM>>8)) count=1 2>/dev/null)"
I'm not sure how portable /dev/urandom is.
The other thing, that "really random" numbers are an overkill, and
it may be easier to use pre-defined numbers,
Right, there are a few reasons not to use /dev/urandom:
- it's not portable
- if we have to generate a lot of numbers, it drains the system's
entropy pool, which is an unfriendly thing to do (and may also be
slow)
- it makes our tests random! This sounds like a good thing, but it
means that if some input happens to cause failure, you are unlikely
to be able to reproduce it.
Instead, use test-genrandom, which is an LCG that starts at a seed. So
you get a large amount of random-ish quickly and portably, and you get
the same data each time.
Thank you! That's exactly what I need here :-)
- Lars