[x] assertions should be along the lines of "given this overlay, this value should/should not be found"
[x] remove result files
[x] make a note that the json folder is used as a basis for tests
[x] get json tests working again
[x] get yaml tests working again
[x] convert yaml tests to first drop yaml converted copies of json input into a temp folder and read in new objects from that, check their equality against json data