To see the problem:

• enter the nix environment with nix develop .#
• go to ./clash and try cabal test to see the haskell tests run (and pass)
• go to ./clash/sim and run python test_top.py to see the simulator test run. Technically it passes but that's because there's no real test, if you look at the log output you can see the problem.

then to make it pass:

• remove axiPassthrough from ethAxisCircuit and re-run the simulator test