I made changes to mk-query-digest yesterday that I didn’t expect to cause any adverse affects. On the contrary, several tests began to fail because a single new but harmless line began to appear in the expected output: “Databases 0″. Perhaps I’m preaching to the choir, as you are all fantastic, thorough and flawless programmers, but as for myself I’ve learned to never take a single failed test for granted.
One time a test failed because some values differed by a millisecond or two. Being curious I investigated and found that our standard deviation equation was just shy of perfect. I fixed it and spent hours cross-checking the myriad tiny values with my TI calculator. Probably no one cared about 0.023 vs. 0.022 but it’s the cultivation of a disposition towards perfection that matters.
My innocuous changes yesterday introduced a case of [Read more...]