Firstly, I commend you on your work.

Second, I looked into your tests directory and from first impressions there's not much there. What is there is kinda messy and not conducive to thorough testing.

If I could make a suggestion: you should look at reusing the work of others. You are in the lucky position where some work has been done for you! There's a massive amount of tests for RISC-V that already exist at https://github.com/riscv/riscv-tests (by weird coincidence someone posted links about this in another thread a few days ago!)

If I were you I would be going through that stuff to try figure out how to get those tests running in my environment. E.g. You have to compile a test and create a mechanism to load the binary into your testbench memory or whatever.