The deep-equal function is fairly complex, but there is pretty minimal test coverave.  Most of the tests compare atomic items, and those are useful.  There are a few tests for non-singleton atomic sequences, but not many.  Worst, the few tests for comparing nodes and nodes sequences are pretty useless.  They seesm to fit this pattern:
  deep-equal($input-context1/PATH, $input-context1/PATH)
I.e. the same expression yielding the same *identical* nodes for both arguments.  An implementation that just tests node identity would pass.