I also now always use Zig to write tests and benchmarks for C code.

This is for example the case in libaegis: https://github.com/jedisct1/libaegis

Calling C functions from Zig is easy (C headers can be imported directly) and doesn't have any overhead. So I can take advantage of the convenience of Zig, even if the tested code only requires a C compiler.

I also now always add Zig build files as an alternative to make/libtool/automake/cmake/meson/etc. The main advantage is that cross-compilation to many targets is supported out of the box, including to WebAssembly. So I can quickly test if the C code compiles fine before actually trying to run it on an emulator.