NF: add cmp_pkg_version function and test

Add function to compare our package version to others.  We'll use this
to see whether the deprecations have expired.

Author: matthew-brett

nibabel/info.py

@@ -1,9 +1,13 @@
-""" This file contains defines parameters for nibabel that we use to fill
-settings in setup.py, the nibabel top-level docstring, and for building the
-docs.  In setup.py in particular, we exec this file, so it cannot import
-nibabel
+""" Define distrubution parameters for nibabel, including package version
+
+This file contains defines parameters for nibabel that we use to fill settings
+in setup.py, the nibabel top-level docstring, and for building the docs.  In
+setup.py in particular, we exec this file, so it cannot import nibabel.
 """
 
+import re
+from distutils.version import StrictVersion
+
 # nibabel version information.  An empty _version_extra corresponds to a
 # full release.  '.dev' as a _version_extra string means this is a development
 # version
@@ -19,6 +23,51 @@
                               _version_micro,
                               _version_extra)
 
+
+_VERSION_RE = re.compile(r'([0-9.]*\d+)(.*)')
+
+
+def _parse_version(version_str):
+    """ Parse version string `version_str` in our format
+    """
+    match = re.match('([0-9.]*\d)(.*)', version_str)
+    if match is None:
+        raise ValueError('Invalid version ' + version_str)
+    return match.groups()
+
+
+def _cmp(a, b):
+    """ Implementation of ``cmp`` for Python 3
+    """
+    return (a > b) - (a < b)
+
+
+def cmp_pkg_version(version_str, pkg_version_str=__version__):
+    """ Compare `version_str` to current package version
+
+    Parameters
+    ----------
+    version_str : str
+        Version string to compare to current package version
+    pkg_version_str : str, optional
+        Version of our package.  Optional, set fom ``__version__`` by default.
+
+    Returns
+    -------
+    version_cmp : int
+        1 if `version_str` higher version than `pkg_version`, 0 if same, -1 if
+        lower.
+    """
+    version, extra = _parse_version(version_str)
+    pkg_version, pkg_extra = _parse_version(pkg_version_str)
+    if version != pkg_version:
+        return _cmp(StrictVersion(version), StrictVersion(pkg_version))
+    return (0 if extra == pkg_extra
+            else 1 if extra == ''
+            else -1 if pkg_extra == ''
+            else _cmp(extra, pkg_extra))
+
+
 CLASSIFIERS = ["Development Status :: 4 - Beta",
                "Environment :: Console",
                "Intended Audience :: Science/Research",

nibabel/tests/test_info.py

@@ -0,0 +1,47 @@
+""" Testing info module
+"""
+
+import nibabel as nib
+from nibabel import info
+from nibabel.info import cmp_pkg_version
+
+from nose.tools import (assert_raises, assert_equal)
+
+
+def test_version():
+    # Test info version is the same as our own version
+    assert_equal(info.__version__, nib.__version__)
+
+
+def test_cmp_pkg_version():
+    # Test version comparator
+    assert_equal(cmp_pkg_version(info.__version__), 0)
+    assert_equal(cmp_pkg_version('0.0'), -1)
+    assert_equal(cmp_pkg_version('1000.1000.1'), 1)
+    assert_equal(cmp_pkg_version(info.__version__, info.__version__), 0)
+    for test_ver, pkg_ver, exp_out in (('1.0', '1.0', 0),
+                                       ('1.0.0', '1.0', 0),
+                                       ('1.0', '1.0.0', 0),
+                                       ('1.1', '1.1', 0),
+                                       ('1.2', '1.1', 1),
+                                       ('1.1', '1.2', -1),
+                                       ('1.1.1', '1.1.1', 0),
+                                       ('1.1.2', '1.1.1', 1),
+                                       ('1.1.1', '1.1.2', -1),
+                                       ('1.1', '1.1dev', 1),
+                                       ('1.1dev', '1.1', -1),
+                                       ('1.2.1', '1.2.1rc1', 1),
+                                       ('1.2.1rc1', '1.2.1', -1),
+                                       ('1.2.1rc1', '1.2.1rc', 1),
+                                       ('1.2.1rc', '1.2.1rc1', -1),
+                                       ('1.2.1rc1', '1.2.1rc', 1),
+                                       ('1.2.1rc', '1.2.1rc1', -1),
+                                       ('1.2.1b', '1.2.1a', 1),
+                                       ('1.2.1b', '1.2.1a', 1),
+                                      ):
+        assert_equal(cmp_pkg_version(test_ver, pkg_ver), exp_out)
+    assert_raises(ValueError, cmp_pkg_version, 'foo.2')
+    assert_raises(ValueError, cmp_pkg_version, 'foo.2', '1.0')
+    assert_raises(ValueError, cmp_pkg_version, '1.0', 'foo.2')
+    assert_raises(ValueError, cmp_pkg_version, '1')
+    assert_raises(ValueError, cmp_pkg_version, 'foo')