IIUC most of the tests are simply from ctags anyway, many of their names relate to ctags bug reports
IIUC the tests are just one (or more) source file(s) mentioned in `Makefile.am` and tags file(s) with the same name but extension `.tags` (generated by Geany, they are tagmanager format, which is binary, so not manually generated). I think mentioning the source files in `Makefile.am` sources list makes the existing test harness feed the source to Geany and generate and compare to the tags files.