feat: add feature to edit email settings, basic message preview

tests/test_emails.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8; -*-
+
+from wuttjamaican.testing import DataTestCase
+from wuttjamaican.email import EmailSetting
+
+from wuttaweb import emails as mod
+
+
+class TestAllSettings(DataTestCase):
+
+    def check_setting(self, setting):
+        self.assertIsNotNone(setting.default_subject)
+        setting = setting(self.config)
+        context = setting.sample_data()
+        self.assertIsInstance(context, dict)
+
+    def test_all(self):
+        for name in dir(mod):
+            obj = getattr(mod, name)
+            if (isinstance(obj, type)
+                and obj is not EmailSetting
+                and issubclass(obj, EmailSetting)):
+                self.check_setting(obj)