diff --git a/dav_base/tests/test_config.py b/dav_base/tests/test_config.py
index d2ed44c..a90402e 100644
--- a/dav_base/tests/test_config.py
+++ b/dav_base/tests/test_config.py
@@ -68,6 +68,11 @@ class AppSettingsTestCase(SimpleTestCase):
         self.app_name = 'dav_base'
         self.test_setting_value = TEST_SETTING_VALUE
 
+    def test_no_settings_file(self):
+        """Test that nothing bad happens if no settings file can be read"""
+        app_settings = AppSettings('', ())
+        self.assertIsInstance(app_settings, AppSettings)
+
     def test_defaults(self):
         """Test the default value for optional and unset settings"""
         default_settings = (
@@ -78,15 +83,39 @@ class AppSettingsTestCase(SimpleTestCase):
         self.assertEqual(app_settings.no_test_setting, 1)
         self.assertEqual(app_settings.no_test_setting_2, 2)
 
-    def test_improperlyconfigured(self):
+    def test_improperlyconfigured_by_class(self):
         """Test if mandatory but unset setting raise correct exception"""
         default_settings = (
             DefaultSetting('no_test_setting', ImproperlyConfigured),
         )
-        try:
+        with self.assertRaisesRegex(ImproperlyConfigured, 'NO_TEST_SETTING must be defined in main.settings-dav_base'):
+            app_settings = AppSettings(self.app_name, default_settings)
+
+    def test_improperlyconfigured_by_instance(self):
+        """Test if mandatory but unset setting raise correct exception"""
+        default_settings = (
+            DefaultSetting('no_test_setting', ImproperlyConfigured('Some Error Message')),
+        )
+        with self.assertRaisesRegex(ImproperlyConfigured, 'Some Error Message'):
+            app_settings = AppSettings(self.app_name, default_settings)
+
+    def test_improperlyconfigured_by_func(self):
+        """Test if invalid setting raise correct exception"""
+        def validator(value):
+            return False
+        default_settings = (
+            DefaultSetting('test_setting', 1, validator=validator),
+        )
+        with self.assertRaises(ImproperlyConfigured):
+            app_settings = AppSettings(self.app_name, default_settings)
+
+    def test_improperlyconfigured_by_regex(self):
+        """Test if invalid setting raise correct exception"""
+        default_settings = (
+            DefaultSetting('test_setting', 1, validator=r'^[01]$'),
+        )
+        with self.assertRaises(ImproperlyConfigured):
             app_settings = AppSettings(self.app_name, default_settings)
-        except ImproperlyConfigured as e:
-            self.assertEqual(str(e), 'NO_TEST_SETTING must be defined in main.settings-dav_base')
 
     def test_settings_from_file(self):
         """Test if value from settings file eliminate exception"""