Fixed call to `ugettext`, which is imported as `_`.

Changed raise to conform to PEP 3109 and wrapped the long line.
Added beginnings of tests for model fields.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@5778 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/__init__.py

@@ -620,7 +620,8 @@ class DecimalField(Field):
         try:
             return decimal.Decimal(value)
         except decimal.InvalidOperation:
-            raise validators.ValidationError, ugettext("This value must be a decimal number.")
+            raise validators.ValidationError(
+                _("This value must be a decimal number."))
 
     def _format(self, value):
         if isinstance(value, basestring):

tests/regressiontests/model_fields/tests.py

+"""
+>>> from django.db.models.fields import *
+
+# DecimalField
+
+>>> f = DecimalField()
+
+>>> f.to_python(3)
+Decimal("3")
+
+>>> f.to_python("3.14")
+Decimal("3.14")
+
+>>> f.to_python("abc")
+Traceback (most recent call last):
+...
+ValidationError: [u'This value must be a decimal number.']
+"""