[soc2009/model-validation] Added first validator with tests

No usefull error message yet, validator isn't used anywhere, just a
mockup basically

git-svn-id: http://code.djangoproject.com/svn/django/branches/soc2009/model-validation@10898 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/validators.py

@@ -0,0 +1,7 @@
+from django.core.exceptions import ValidationError
+
+def validate_integer(value, all_values={}, model_instance=None):
+    try:
+        int(value)
+    except (ValueError, TypeError), e:
+        raise ValidationError('')

tests/modeltests/validators/tests.py

@@ -0,0 +1,33 @@
+from unittest import TestCase
+
+from django.core.exceptions import ValidationError
+from django.core.validators import validate_integer
+
+class TestSimpleValidators(TestCase):
+    pass
+
+SIMPLE_VALIDATORS_VALUES = (
+    (validate_integer, '42', None),
+    (validate_integer, '-42', None),
+    (validate_integer, -42, None),
+    (validate_integer, -42.5, None),
+    (validate_integer, None, ValidationError),
+    (validate_integer, 'a', ValidationError),
+)
+
+def get_simple_test_func(expected, value, num):
+    if isinstance(expected, type) and issubclass(expected, ValidationError):
+        test_mask = 'test_%s_raises_error_%d'
+        def test_func(self):
+            self.assertRaises(expected, validator, value)
+    else:
+        test_mask = 'test_%s_%d'
+        def test_func(self):
+            self.assertEqual(expected, validator(value))
+    test_name = test_mask % (validator.__name__, num)
+    return test_name, test_func
+
+test_counter = {}
+for validator, value, expected in SIMPLE_VALIDATORS_VALUES:
+    num = test_counter[validator] = test_counter.setdefault(validator, 0) + 1
+    setattr(TestSimpleValidators, *get_simple_test_func(expected, value, num))