Use exceptions in place of assertions -> VersionError

picard/__init__.py

@@ -25,9 +25,15 @@ PICARD_ORG_NAME = "MusicBrainz"
 PICARD_VERSION = (1, 3, 0, 'dev', 2)
 
 
+class VersionError(Exception):
+    pass
+
+
 def version_to_string(version, short=False):
-    assert len(version) == 5
-    assert version[3] in ('final', 'dev')
+    if len(version) != 5:
+        raise VersionError("Length != 5")
+    if version[3] not in ('final', 'dev'):
+        raise VersionError("Should be either 'final' or 'dev'")
     _version = []
     for p in version:
         try:
@@ -47,9 +53,14 @@ def version_to_string(version, short=False):
     return version_str
 
 
+_version_re = re.compile("^(\d+)[._](\d+)[._](\d+)[._]?(dev|final)[._]?(\d+)$")
 def version_from_string(version_str):
-    g = re.match(r"^(\d+)[._](\d+)[._](\d+)[._]?(dev|final)[._]?(\d+)$", version_str).groups()
-    return (int(g[0]), int(g[1]), int(g[2]), g[3], int(g[4]))
+    m = _version_re.search(version_str)
+    if m:
+        g = m.groups()
+        return (int(g[0]), int(g[1]), int(g[2]), g[3], int(g[4]))
+    raise VersionError("String '%s' do not match regex '%s'" % (version_str,
+                                                                _version_re.pattern))
 
 
 __version__ = PICARD_VERSION_STR = version_to_string(PICARD_VERSION)

test/test_versions.py

@@ -1,7 +1,9 @@
 # -*- coding: utf-8 -*-
 
 import unittest
-from picard import version_to_string, version_from_string
+from picard import (version_to_string,
+                    version_from_string,
+                    VersionError)
 
 
 class VersionsTest(unittest.TestCase):
@@ -23,8 +25,8 @@ class VersionsTest(unittest.TestCase):
 
     def test_version_conv_4(self):
         l, s = (1, 0, 2, '', 0), '1.0.2'
-        self.assertRaises(AssertionError, version_to_string, (l))
-        self.assertRaises(AttributeError, version_from_string, (s))
+        self.assertRaises(VersionError, version_to_string, (l))
+        self.assertRaises(VersionError, version_from_string, (s))
 
     def test_version_conv_5(self):
         l, s = (999, 999, 999, 'dev', 999), '999.999.999dev999'
@@ -33,7 +35,7 @@ class VersionsTest(unittest.TestCase):
 
     def test_version_conv_6(self):
         l = (1, 0, 2, 'xx', 0)
-        self.assertRaises(AssertionError, version_to_string, (l))
+        self.assertRaises(VersionError, version_to_string, (l))
 
     def test_version_conv_7(self):
         l, s = (1, 1, 0, 'final', 0), '1.1'