ELLCC has a few simple (for now) regression tests that are run after every new build. See this page for more information. A primary goal of ELLCC is to support a POSIX environment for both Linux and standalone (bare metal) embedded systems. To that end, I’ve recently started looking at open source test suites that check for POSIX compliance. One that I’ve found is the Open POSIX Test Suite.
I’ve looked at it a bit and it seems to be a good starting point for testing the ELLCC libraries. Unfortunately, it hasn’t been updated since 2005 so it is a little out of date.
I’ve worked on it a little bit to play better with a more modern Linux release (Fedora 16). I’m currently building the test suite against GCC and plan to build against the ecc compiler as a next step. (ecc uses the host header files and libraries to build programs. In other words, it is pretty similar to using clang/LLVM.) After that, I plan to build and test using libecc, the ELLCC standard libraries based on the NetBSD sources. If you’d like to follow the progress, I’m keeping the updated source in the ELLCC source repository.