https://en.wikipedia.org/wiki/Argument_from_ignorance
It is an absolute quality of life issue for development. The longer tests take to run, the more loathe developers are to write and work with them. The worst is when developers start to add calls to `sleep()` in order to make async tests work properly... it just balloons out of there and becomes an extremely brittle test suite.
HN has been chock full of blogs for years from big and small firms that talk about how they sped up the build process. Updating hardware, compilers, architecture refactoring etc, compilers and adding optimization flags could affect the run time of a test, outside of one that literally has some `sleep(...)` call in it, in which case this report is also fairly useless.
And most of the times, they were avoidable, and fixed after we realized what happened.
