Agreed. As much as I want it to be simpler to build C++ programs from source, it's pretty much always _possible_ in my experience, it can just a PITA frequently.

I think that tests are a sure-fire way to improve the quality of your code, but I'd throw another piece in to the ring: sanitizers [0]. Projects that have good tests and run them regularly with TSan/ASan/UBSan in my experience are much better to work on because it means that it's much less likely there's deep seeded issues that are lurking. It gives you increased confidence that you're not introducing hard-to-detect issues as you go.

These tools aren't just exclusive to C++. I've said the same thing about C, Go, Zig, Odin, etc. Projects that use them (and have good automated tests) tend to be in good shape, and projects that don't tend to take a long time to make any progress on.

[0] https://github.com/google/sanitizers