On 90e37ea088b8ab5ff0d3c4f92c7205f8acdd8d09 from master,
mcomix is failing to run its testsuite:

[...]
copying mcomix/images/tango-add-bookmark.png -> build/lib/mcomix/images
copying mcomix/images/zoom.png -> build/lib/mcomix/images
copying mcomix/images/tango-enhance-image.png -> build/lib/mcomix/images
phase `build' succeeded after 0.3 seconds
starting phase `check'
running "python setup.py" with command "test" and parameters ()
running test
running egg_info
writing requirements to mcomix.egg-info/requires.txt
writing mcomix.egg-info/PKG-INFO
writing top-level names to mcomix.egg-info/top_level.txt
writing dependency_links to mcomix.egg-info/dependency_links.txt
writing entry points to mcomix.egg-info/entry_points.txt
warning: manifest_maker: standard file '-c' not found

reading manifest file 'mcomix.egg-info/SOURCES.txt'
reading manifest template 'MANIFEST.in'
warning: no previously-included files found matching 
'mcomix/images/mcomix-large.png'
writing manifest file 'mcomix.egg-info/SOURCES.txt'
running build_ext
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "setup.py", line 110, in <module>
    'Operating System :: POSIX :: BSD'],
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/distutils/core.py", 
line 151, in setup
    dist.run_commands()
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/distutils/dist.py", 
line 953, in run_commands
    self.run_command(cmd)
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/distutils/dist.py", 
line 972, in run_command
    cmd_obj.run()
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/site-packages/setuptools/command/test.py", 
line 210, in run
    self.run_tests()
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/site-packages/setuptools/command/test.py", 
line 231, in run_tests
    testRunner=self._resolve_as_ep(self.test_runner),
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/unittest/main.py", 
line 94, in __init__
    self.parseArgs(argv)
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/unittest/main.py", 
line 149, in parseArgs
    self.createTests()
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/unittest/main.py", 
line 158, in createTests
    self.module)
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/unittest/loader.py", 
line 130, in loadTestsFromNames
    suites = [self.loadTestsFromName(name, module) for name in names]
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/unittest/loader.py", 
line 103, in loadTestsFromName
    return self.loadTestsFromModule(obj)
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/site-packages/setuptools/command/test.py", 
line 42, in loadTestsFromModule
    tests.append(self.loadTestsFromName(submodule))
  File 
"/gnu/store/j4vj7h3wyb532g2j0axzjj43z2a0dg81-python-2.7.14/lib/python2.7/unittest/loader.py", 
line 100, in loadTestsFromName
    parent, obj = obj, getattr(obj, part)
AttributeError: 'module' object has no attribute 'test_support'
phase `check' failed after 0.3 seconds
builder for 
`/gnu/store/6031jjx3pnw3m4wkbng2sfz6w4cv3x22-mcomix-1.2.1.drv' failed 
with exit code 1
guix package: error: build failed: build of 
`/gnu/store/6031jjx3pnw3m4wkbng2sfz6w4cv3x22-mcomix-1.2.1.drv' failed


-- 
ng0 :: https://crash.cx
A88C8ADD129828D7EAC02E52E22F9BBFEE348588 :: https://crash.cx/keys/