Implement name normalization from PEP 503

CHANGELOG.rst

@@ -6,6 +6,8 @@ Changelog
 
 .. note:: This version is not yet released and is under active development.
 
+* Add a function that implements the name canonicalization from PEP 503.
+
 
 16.1 - 2016-02-07
 ~~~~~~~~~~~~~~~~~

docs/index.rst

@@ -24,6 +24,7 @@ API
     specifiers
     markers
     requirements
+    utils
 
 
 Project

docs/utils.rst

@@ -0,0 +1,28 @@
+Utilities
+=========
+
+.. currentmodule:: packaging.utils
+
+
+A set of small, helper utilities for dealing with Python packages.
+
+
+Reference
+---------
+
+.. function:: canonicalize_name(name)
+
+    This function takes a valid Python package name, and returns the normalized
+    form of it.
+
+    :param str name: The name to normalize.
+
+    .. doctest::
+
+        >>> from packaging.utils import canonicalize_name
+        >>> canonicalize_name("Django")
+        'django'
+        >>> canonicalize_name("oslo.concurrency")
+        'oslo-concurrency'
+        >>> canonicalize_name("requests")
+        'requests'

packaging/utils.py

@@ -0,0 +1,14 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import re
+
+
+_canonicalize_regex = re.compile(r"[-_.]+")
+
+
+def canonicalize_name(name):
+    # This is taken from PEP 503.
+    return _canonicalize_regex.sub("-", name).lower()

tests/test_utils.py

@@ -0,0 +1,27 @@
+# This file is dual licensed under the terms of the Apache License, Version
+# 2.0, and the BSD License. See the LICENSE file in the root of this repository
+# for complete details.
+from __future__ import absolute_import, division, print_function
+
+import pytest
+
+from packaging.utils import canonicalize_name
+
+
+@pytest.mark.parametrize(
+    ("name", "expected"),
+    [
+        ("foo", "foo"),
+        ("Foo", "foo"),
+        ("fOo", "foo"),
+        ("foo.bar", "foo-bar"),
+        ("Foo.Bar", "foo-bar"),
+        ("Foo.....Bar", "foo-bar"),
+        ("foo_bar", "foo-bar"),
+        ("foo___bar", "foo-bar"),
+        ("foo-bar", "foo-bar"),
+        ("foo----bar", "foo-bar"),
+    ],
+)
+def test_canonicalize_name(name, expected):
+    assert canonicalize_name(name) == expected