BUG: import full module path in npy_load_module

[jjhelmus]

Use the full module path when importing importlib.machinery for use in the
npy_load_module function. Just importing importlib is not sufficient in certain
cases, for example Python 3.4.

closes #8147

[njsmith]

Change looks good but can we get a test?

[jjhelmus]

Was thinking about the following as a test:

def test_npy_load_module_py34():
    with tempdir(prefix="numpy_test_compat_") as folder:
        filename = join(folder, 'example.py')
        with open(filename, 'w') as f:
            f.write("magic_number = 42")
        example = npy_load_module('example', filename)
        assert_(example.magic_number == 42)

The issue is that this passes with or without the proposed fix. Outside of the test suite the assert will fail without the fix but inside the test suite it always passes.

[jjhelmus]

Fun, machinery is not in the importlib module namespace if imported alone, but it is after nose is imported:

Python 3.4.5 |Continuum Analytics, Inc.| (default, Jul  2 2016, 17:47:57)
[GCC 4.2.1 Compatible Apple LLVM 4.2 (clang-425.0.28)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import importlib
>>> dir(importlib)
['_RELOADING', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__import__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '_bootstrap', '_imp', '_r_long', '_w_long', 'find_loader', 'import_module', 'invalidate_caches', 'reload', 'sys', 'types', 'warnings']
>>> import nose
>>> dir(importlib)
['_RELOADING', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__import__', '__loader__', '__name__', '__package__', '__path__', '__spec__', '_bootstrap', '_imp', '_r_long', '_w_long', 'find_loader', 'import_module', 'invalidate_caches', 'machinery', 'reload', 'sys', 'types', 'util', 'warnings']

I'm at a loss on how write a test that changes from pass to fail with the proposed modification.

[njsmith]

Ugh, wow.

Hail mary: subprocess.run([sys.executable, "-c", "import numpy; numpy.npy_load_module(..."])?

Or if it's not doable we can skip it.

[charris]

@njsmith I'm going to put this in, figuring out how to test it looks to be more trouble than it is worth.

[charris]

Thanks @jjhelmus .

[jakirkham]

Would this be backported to 1.11?