ctest -R testoctave passes!
This is actually wrong changes. This test is almost fine - the command should produce image result. Testing as "not text result" not actually correct, yes, and this is already fixed in the commit d700f7be39d204b370a351330ebd4fdadd6ff9dd. So, I think, this changes should be canceled.
Also, if you have a problems with Octave tests, you should enable plot integration in Octave settings.