first failing test
make it pass
start to promote this to a quick check pattern, currently failing
encode it with a property
quickchcek not appropriate
read the rules properly
failing test
minimal viable pass
failing test
minimal viable pass
eliminate duplication
failing test for dead
and now its passing
non-exhaustive pattern match failure
well, tests pass
next stage is to refactor to rules as data; not code
glorious failing tests
now it just passes
get rid of a bit more duplication
rename