This article is pretty biased against Guile. Guile-Emacs was a very neat experiment and the fact that it worked at all was remarkable but the prototype didn't get traction with the Emacs devs. It should be no surprise that it has issues because it was never completed! That's not an indictment of Guile or Emacs (both are wonderful), there just wasn't the necessary desire to make it happen so it fizzled out.
Guile-emacs also used a lot of Emacs functions for elisp functionality. The author is trying to draw conclusions from the test suite failing, but forgot to include a large chunk of the run-time.
