TST: fix misc. doctest failures (test_doc.py)

[grlee77]

test_doc.py was apparently not being run on the CI services and had a number of failures.

[grlee77]

Thanks to @rafat for pointing out the issue in openjournals/joss-reviews#1237

It seems that nosetests was skipping test_doc.py entirely, so I modified the .travis.yml to run the tests in this file with a separate python call.

[grlee77]

If I don't hear any objections I'll go ahead and merge this one soon.

I'm not a fan of doctests in general, but since we have them currently, we should run them on CI to make sure they don't get out of date like this in the future.

[rgommers]

Thanks @grlee77. All green, so helpful for now.

I'm not a fan of doctests in general, but since we have them currently, we should run them on CI to make sure they don't get out of date like this in the future.

Agreed. I actually like examples in doctest format, the problem is just that doctest itself is terrible. https://github.com/scipy/scipy/blob/master/tools/refguide_check.py fixes that. we can copy that at some point if needed (or wait till it gets turned in a standalone package).

[grlee77]

https://github.com/scipy/scipy/blob/master/tools/refguide_check.py fixes that. we can copy that at some point if needed (or wait till it gets turned in a standalone package).

Actually we already have it in util/refguide_check.py and one of the Travis cases calls it, but perhaps it is not configured correctly? It currently only seems to check the examples in the demos folder, but doesn't actually seem to run any doctests.

[rgommers]

Ah good catch. It will need the --doctests flag.

[grlee77]

Ah good catch. It will need the --doctests flag.

I tried that, but it doesn't seem to do anything. The full output is

Running checks for 0 modules:
Checking examples files at /home/lee8rx/my_git/pyir/pywt/doc/source/regression/*.rst:

dwt-idwt.rst .
gotchas.rst .
index.rst .
modes.rst .
multilevel.rst .
wavelet.rst .
wp.rst .
wp2d.rst .

OK: refguide and doctests checks passed!

For comparison, python pywt/tests/test_doc.py outputs

.........................................
----------------------------------------------------------------------
Ran 41 tests in 0.039s

OK

Finally there is the ability to run make doctest from within the doc folder. I don't think this is currently done on CI, but the summary produced by that is:

Doctest summary
===============
  379 tests
    0 failures in tests
    0 failures in setup code
    0 failures in cleanup code

I think it is more than the above mainly due to inclusion of additional regression tests from doc/source/regression/