Raise ValueError in the case of bad input.

src/utils.py

@@ -175,10 +175,11 @@ _soundextrans = string.maketrans(string.ascii_uppercase,
 _notUpper = string.ascii.translate(string.ascii, string.ascii_uppercase)
 def soundex(s, length=4):
     """Returns the soundex hash of a given string."""
-    assert s
     s = s.upper() # Make everything uppercase.
-    firstChar = s[0] # Save the first character.
     s = s.translate(string.ascii, _notUpper) # Delete non-letters.
+    if not s:
+        raise ValueError, 'Invalid string for soundex: %s'
+    firstChar = s[0] # Save the first character.
     s = s.translate(_soundextrans) # Convert to soundex numbers.
     s = s.lstrip(s[0]) # Remove all repeated first characters.
     L = [firstChar]

test/test_utils.py

@@ -98,6 +98,9 @@ class UtilsTest(unittest.TestCase):
             soundex = utils.soundex(name)
             self.assertEqual(soundex, key,
                              '%s was %s, not %s' % (name, soundex, key))
+        self.assertRaises(ValueError, utils.soundex, '3')
+        self.assertRaises(ValueError, utils.soundex, "'")
+        
 
     def testDQRepr(self):
         L = ['foo', 'foo\'bar', 'foo"bar', '"', '\\', '', '\x00']