I changed 5 to _MAX_LINES.

Other than trivial duplication, I think each test example should be added for a reason, because there is something different about it that might conceivably cause a failure. For example, there should be a case with more than _MAX_LINES in the docstring. But I think one is enough to make sure we split with maxsplit. And I think one text wrap is enough.

The many 't#' test functions were needed for 2.x because it has 12 lines of complicated code that were replaced here by 1.
   argspec = inspect.formatargspec(*inspect.getfullargspec(fob))
For 3.x, we would not need as many tests if the inspect methods were adequately tested and debugged. However, they were not fixed to handle keyword only args until 3.4 and they are still in flux.

The attached patch will need adjustment for 2.7 (I believe) and 3.4 (because *,... is handled better). I plan to do so when fresher.