Failure with 3.4.0c1:

[170/394/5] test_importlib
test test_importlib failed -- Traceback (most recent call last):
  File "C:\Programs\Python34.32\lib\unittest\case.py", line 57, in testPartExecutor
    yield
  File "C:\Programs\Python34.32\lib\unittest\case.py", line 574, in run
    testMethod()
  File "C:\Programs\Python34.32\lib\unittest\loader.py", line 32, in testFailure
    raise exception
ImportError: Failed to import test module: test.test_importlib.source.test_abc_loader
Traceback (most recent call last):
  File "C:\Programs\Python34.32\lib\unittest\loader.py", line 312, in _find_tests
    module = self._get_module_from_name(name)
  File "C:\Programs\Python34.32\lib\unittest\loader.py", line 290, in _get_module_from_name
    __import__(name)
  File "C:\Programs\Python34.32\lib\test\test_importlib\source\test_abc_loader.py", line 73, in <module>
    class PyLoaderMock(abc.PyLoader):
AttributeError: 'module' object has no attribute 'PyLoader'

On the other hand, the test passes on a fresh debug build.