Mock import of ctypes fails with unsupported operand

[maphew]

I have small Windows module that relies on the ctypes core module. On the project RTD site the page for the module comes up empty. Looking at the latest almost successful build log https://readthedocs.org/builds/apt/2900858/ there is a failure during make html stage.

  File "/var/build/user_builds/apt/checkouts/latest/knownpaths.py", line 5, in <module>
    from ctypes import windll, wintypes
  File "/usr/lib/python2.7/ctypes/wintypes.py", line 23, in <module>
    class VARIANT_BOOL(_SimpleCData):
ValueError: _type_ 'v' not supported

Following the FAQ entry https://read-the-docs.readthedocs.org/en/latest/faq.html#i-get-import-errors-on-libraries-that-depend-on-c-modules I tried to fake import ctypes using mock, but doing so cause the build to fail completely. From what I can tell, but I'm no means an expert in this area, it's because mock itself is missing some math functions:

  File "/var/build/user_builds/apt/checkouts/latest/knownpaths.py", line 13, in GUID
    ("Data4", wintypes.BYTE * 8)
TypeError: unsupported operand type(s) for *: 'Mock' and 'int'

Full details of the trouble and steps taken so far at maphew/apt#48

Am I following the right path? Can ctypes be used in a project on RTD and I just need to persevere?

[maphew]

Initially I thought it was ctypes itself that needed to be mocked, but
it turns out I needed to work closer to home and mock the module which
calls ctypes, not ctypes itself.

- MOCK_MODULES = ['ctypes']
+ MOCK_MODULES = ['knownpaths']

Thank you to @Dunes on stack Overflow for guiding me in the right direction
http://stackoverflow.com/questions/30950870/mock-import-of-ctypes-fails-with-unsupported-operand-on-read-the-docs/