Add the ability to validate default options value

Currently, the default options value provided are not validated, which
can trigger fun things like a IntOpt having a "foobar" as default value,
with code failing later when the option is being used.

This patch introduces a _validate_value method that can be used to
validate the default value to the expected type.

ConfigOpts.__call__ gains a validate_default_values arguments that can
trigger default value validation. The argument is False by default in
order to not break existing code.

Ultimately, we could in a later version validate the default at Opt
object creation time, which would be much better, but that may break
existing code, so we'll see.

Change-Id: I6c1998a3be3f1579139317cd85d56b42cabf89db

1 files changed, 36 insertions, 1 deletions

diff --git a/tests/test_cfg.py b/tests/test_cfg.py
index b5a8c60..c074a1d 100644
--- a/tests/test_cfg.py
+++ b/tests/test_cfg.py
@@ -88,7 +88,8 @@ class BaseTestCase(utils.BaseTestCase):
                 prog='test',
                 version='1.0',
                 usage='%(prog)s FOO BAR',
-                default_config_files=default_config_files)
+                default_config_files=default_config_files,
+                validate_default_values=True)
 
     def setUp(self):
         super(BaseTestCase, self).setUp()
@@ -790,6 +791,18 @@ class ConfigFileOptsTestCase(BaseTestCase):
         self.assertTrue(hasattr(self.conf, 'foo'))
         self.assertEqual(self.conf.foo, 666)
 
+    def test_conf_file_int_wrong_default(self):
+        self.conf.register_opt(cfg.IntOpt('foo', default='t666'))
+
+        paths = self.create_tempfiles([('test',
+                                        '[DEFAULT]\n')])
+
+        self.conf(['--config-file', paths[0]])
+        self.assertRaises(AttributeError,
+                          getattr,
+                          self.conf,
+                          'foo')
+
     def test_conf_file_int_value(self):
         self.conf.register_opt(cfg.IntOpt('foo'))
 
@@ -851,6 +864,18 @@ class ConfigFileOptsTestCase(BaseTestCase):
         self.assertTrue(hasattr(self.conf, 'foo'))
         self.assertEqual(self.conf.foo, 6.66)
 
+    def test_conf_file_float_default_wrong_type(self):
+        self.conf.register_opt(cfg.FloatOpt('foo', default='foobar6.66'))
+
+        paths = self.create_tempfiles([('test',
+                                        '[DEFAULT]\n')])
+
+        self.conf(['--config-file', paths[0]])
+        self.assertRaises(AttributeError,
+                          getattr,
+                          self.conf,
+                          'foo')
+
     def test_conf_file_float_value(self):
         self.conf.register_opt(cfg.FloatOpt('foo'))
 
@@ -2909,6 +2934,16 @@ class ChoicesTestCase(BaseTestCase):
         self.assertTrue(hasattr(self.conf, 'foo'))
         self.assertEqual(self.conf.foo, 'baaar')
 
+    def test_conf_file_choice_bad_default(self):
+        self.conf.register_cli_opt(cfg.StrOpt('foo',
+                                              choices=['baar', 'baaar'],
+                                              default='foobaz'))
+        self.conf([])
+        self.assertRaises(AttributeError,
+                          getattr,
+                          self.conf,
+                          'foobaz')
+
 
 class PrintHelpTestCase(utils.BaseTestCase):