ENH: set correct __module__ for objects in numpy's public API

Fixes GH-12271

Tests verify that everything in ``dir(numpy)`` either has ``__module__`` set to
``'numpy'``, or appears in an explicit whitelist of undocumented functions and
exported bulitins. These should eventually be documented or removed.

I also identified a handful of functions for which I had accidentally not setup
dispatch for with ``__array_function__`` before, because they were listed under
"ndarray methods" in ``_add_newdocs.py``. I guess that should be a lesson in
trusting code comments :).

1 files changed, 65 insertions, 0 deletions

diff --git a/numpy/tests/test_public_api.py b/numpy/tests/test_public_api.py
new file mode 100644
index 000000000..fcb3a99cf
--- /dev/null
+++ b/numpy/tests/test_public_api.py
@@ -0,0 +1,65 @@
+from __future__ import division, absolute_import, print_function
+
+import numpy as np
+
+
+def check_dir(module, module_name=None):
+    """Returns a mapping of all objects with the wrong __module__ attribute."""
+    if module_name is None:
+        module_name = module.__name__
+    results = {}
+    for name in dir(module):
+        item = getattr(module, name)
+        if (hasattr(item, '__module__') and hasattr(item, '__name__')
+                and item.__module__ != module_name):
+            results[name] = item.__module__ + '.' + item.__name__
+    return results
+
+
+def test_numpy_namespace():
+    # None of these objects are publicly documented.
+    whitelist = {
+        'Tester': 'numpy.testing._private.nosetester.NoseTester',
+        '_add_newdoc_ufunc': 'numpy.core._multiarray_umath._add_newdoc_ufunc',
+        'add_docstring': 'numpy.core._multiarray_umath.add_docstring',
+        'add_newdoc': 'numpy.core.function_base.add_newdoc',
+        'add_newdoc_ufunc': 'numpy.core._multiarray_umath._add_newdoc_ufunc',
+        'bool': 'builtins.bool',
+        'byte_bounds': 'numpy.lib.utils.byte_bounds',
+        'compare_chararrays': 'numpy.core._multiarray_umath.compare_chararrays',
+        'complex': 'builtins.complex',
+        'deprecate': 'numpy.lib.utils.deprecate',
+        'deprecate_with_doc': 'numpy.lib.utils.<lambda>',
+        'disp': 'numpy.lib.function_base.disp',
+        'fastCopyAndTranspose': 'numpy.core._multiarray_umath._fastCopyAndTranspose',
+        'float': 'builtins.float',
+        'get_array_wrap': 'numpy.lib.shape_base.get_array_wrap',
+        'get_include': 'numpy.lib.utils.get_include',
+        'int': 'builtins.int',
+        'int_asbuffer': 'numpy.core._multiarray_umath.int_asbuffer',
+        'long': 'builtins.int',
+        'mafromtxt': 'numpy.lib.npyio.mafromtxt',
+        'maximum_sctype': 'numpy.core.numerictypes.maximum_sctype',
+        'ndfromtxt': 'numpy.lib.npyio.ndfromtxt',
+        'object': 'builtins.object',
+        'recfromcsv': 'numpy.lib.npyio.recfromcsv',
+        'recfromtxt': 'numpy.lib.npyio.recfromtxt',
+        'safe_eval': 'numpy.lib.utils.safe_eval',
+        'set_string_function': 'numpy.core.arrayprint.set_string_function',
+        'show_config': 'numpy.__config__.show',
+        'str': 'builtins.str',
+        'unicode': 'builtins.str',
+        'who': 'numpy.lib.utils.who',
+    }
+    bad_results = check_dir(np)
+    assert bad_results == whitelist
+
+
+def test_numpy_linalg():
+    bad_results = check_dir(np.linalg)
+    assert bad_results == {}
+
+
+def test_numpy_fft():
+    bad_results = check_dir(np.fft)
+    assert bad_results == {}