Add semantic_version.validate (Closes #2).

Simple way of testing whether a string is a 'valid' SemVer version.

Signed-off-by: Raphaël Barrois <raphael.barrois@polytechnique.org>

doc/changelog.rst

@@ -14,6 +14,8 @@ ChangeLog
     * Add the :meth:`Version.coerce <semantic_version.Version.coerce>` class method to
       :class:`~semantic_version.Version` class for mapping arbitrary version strings to
       semver.
+    * Add the :func:`~semantic_version.validate` method to validate a version
+      string against the SemVer rules.
 
 2.1.2 (22/05/2012)
 ------------------

doc/reference.rst

@@ -43,6 +43,21 @@ Module-level functions
     :rtype: ``bool``
 
 
+.. function:: validate(version)
+
+    Check whether a version string complies with the `SemVer`_ rules.
+
+    .. code-block:: pycon
+
+        >>> semantic_version.validate('1.1.1')
+        True
+        >>> semantic_version.validate('1.2.3a4')
+        False
+
+    :param str version: The version string to validate
+    :rtype: ``bool``
+
+
 Representing a version (the Version class)
 ------------------------------------------
 

src/semantic_version/base.py

@@ -438,3 +438,12 @@ def compare(v1, v2):
 
 def match(spec, version):
     return Spec(spec).match(Version(version))
+
+
+def validate(version_string):
+    """Validates a version string againt the SemVer specification."""
+    try:
+        Version.parse(version_string)
+        return True
+    except ValueError:
+        return False

tests/test_base.py

@@ -88,6 +88,46 @@ class TopLevelTestCase(unittest.TestCase):
             self.assertTrue(base.match(spec, version),
                 "%r should accept %r" % (spec, version))
 
+    valid_strings = (
+        '1.0.0-alpha',
+        '1.0.0-alpha.1',
+        '1.0.0-beta.2',
+        '1.0.0-beta.11',
+        '1.0.0-rc.1',
+        '1.0.0-rc.1+build.1',
+        '1.0.0',
+        '1.0.0+0.3.7',
+        '1.3.7+build',
+        '1.3.7+build.2.b8f12d7',
+        '1.3.7+build.11.e0f985a',
+        '1.1.1',
+        '1.1.2',
+        '1.1.3-rc4.5',
+        '1.1.3-rc42.3-14-15.24+build.2012-04-13.223',
+        '1.1.3+build.2012-04-13.HUY.alpha-12.1',
+    )
+
+    def test_validate_valid(self):
+        for version in self.valid_strings:
+            self.assertTrue(base.validate(version),
+                "%r should be a valid version" % (version,))
+
+    invalid_strings = (
+        '1',
+        'v1',
+        '1.2.3.4',
+        '1.2',
+        '1.2a3',
+        '1.2.3a4',
+        'v12.34.5',
+        '1.2.3+4+5',
+    )
+
+    def test_validate_invalid(self):
+        for version in self.invalid_strings:
+            self.assertFalse(base.validate(version),
+                "%r should not be a valid version" % (version,))
+
 
 class VersionTestCase(unittest.TestCase):
     versions = {