Here is a war story from the Harfbuzz dude: https://docs.google.com/document/d/1wMPwVNBvsIriamcyBO5aNs7Cdr8lmbwLJ8GmZBAswF4 https://docs.google.com/document/d/1

Here is a war story from the Harfbuzz dude: https://docs.google.com/document/d/1wMPwVNBvsIriamcyBO5aNs7Cdr8lmbwLJ8GmZBAswF4 https://docs.google.com/document/d/1wMPwVNBvsIriamcyBO5aNs7C... > It turns out, for many of the scripts we are interested in (Indic-like ones), we have to deal with a word list of around a million items or less to cover all of Wikipedia! That was great, because now I could run the entire test suite for, say, Hindi, and it would take 10 seconds to run [...] For the two years since we have use this test-driven methodology for all changes to the Indic-related shaping logic and has been able to constantly improve the quality of the shaper release after release. So even if you have a great infrastructure in place, it is still years of tuning.