Improve test output for code generator unit tests
Currently, when a codegen test fails you get a lot of text output and you have to manually compare the generated and expected code. This is made worse by the fact that we generate "full" mod files (we cannot generate code just for a function or a little snipped of NMODL code). One possible improvement would be to pass the expected and generated code through a diff tool (or library) and print that. This library could be useful: https://github.com/google/diff-match-patch
Turns out diff-match-patch is a no-go (from their github repo):
The C++ port was created with a dependency on the Qt library. As a result this version is very slow. We are no longer maintaining this version of Diff Match Patch and would welcome anyone interested in creating a replacement version which uses the STL instead.
After some more searching I can't find any modern decent library for this.. There is xdifflib, but that's just awful and I found also https://github.com/cubicdaiya/dtl but that isn't very much maintained...