This is a definition of “serious projects” that excludes almost all serious projects.
I'm not sure, all of mines at big companies have followed this definition.
> This tend to be true for most serious projects, that the amount of test code is greater than that of the code that is being exercised.
Reading this comment, I was thinking "Oh that must mean the test code is 2x or maybe even 3x the amount of source code"
Going to the SQLite web site, I was surprised to find that the test code is 600x larger than the source code. Impressive.
Is this 600:1 ratio typical for other projects? The ones that I have seen are more like 1x or 2x, but I have not worked with many open source systems.
They count post-codegen test LOC, the checked in ratio is much smaller - used to be something like 5:1. Still super impressive!
Test to regular code ratio shouldn’t be impressive by itself anyway, considering how repetitive, duplicated, and setup-heavy test code can be.
I think a good way of looking at the quality of their tests is how they categorize their tests, which focuses on the different types of problems they want to solve: power loss, concurrency, API issues, logic, etc. https://www.sqlite.org/testing.html
This tend to be true for most serious projects, that the amount of test code is greater than that of the code that is being exercised.
I think what they are famous for is the quality of the testing suite, rather than the amount.