Most of time the files are identical, so instead of comparing the TTX
dump we can check sha256 hashes of the files first and if they match, we
don’t have to check the TTX dumps at all, making the subset tests orders
of magnitude faster.
time meson test --suite=subset down from:
real 0m19.418s
user 0m38.171s
sys 0m3.587s
to:
real 0m3.102s
user 0m8.622s
sys 0m1.701s
The expected files have been replaced by hb-subset output so they are
bit-identical where FontTools output might not.
The generate-expected-outputs.py now compares the hb-subset output with
fontttols subset and errors of they don’t match.
Speed-up subset tests by saving TTX dump of expected output instead of
generating it each time the tests are run.
Cuts down meson test --suite=subset on my system from:
real 0m38.977s
user 1m12.024s
sys 0m10.547s
to:
real 0m22.291s
user 0m44.548s
sys 0m9.221s
Part of https://github.com/harfbuzz/harfbuzz/issues/3089
