Add support for Union type annotations for constants

Note that `Optional[x]` is just an alias for `Union[None, x]` so this
effectively supports `Optional` too.

This was especially troublesome because the redis password must be
unset/None in order to avoid authentication, but the test would complain
that `None` isn't a `str`. Setting to an empty string would pass the
test but then make redis authenticate and fail.

1 files changed, 12 insertions, 5 deletions

diff --git a/tests/bot/test_constants.py b/tests/bot/test_constants.py
index dae7c066c..db9a9bcb0 100644
--- a/tests/bot/test_constants.py
+++ b/tests/bot/test_constants.py
@@ -1,4 +1,5 @@
 import inspect
+import typing
 import unittest
 
 from bot import constants
@@ -8,7 +9,7 @@ class ConstantsTests(unittest.TestCase):
     """Tests for our constants."""
 
     def test_section_configuration_matches_type_specification(self):
-        """The section annotations should match the actual types of the sections."""
+        """"The section annotations should match the actual types of the sections."""
 
         sections = (
             cls
@@ -19,8 +20,14 @@ class ConstantsTests(unittest.TestCase):
             for name, annotation in section.__annotations__.items():
                 with self.subTest(section=section, name=name, annotation=annotation):
                     value = getattr(section, name)
+                    annotation_args = typing.get_args(annotation)
 
-                    if getattr(annotation, '_name', None) in ('Dict', 'List'):
-                        self.skipTest("Cannot validate containers yet.")
-
-                    self.assertIsInstance(value, annotation)
+                    if not annotation_args:
+                        self.assertIsInstance(value, annotation)
+                    else:
+                        origin = typing.get_origin(annotation)
+                        if origin is typing.Union:
+                            is_instance = any(isinstance(value, arg) for arg in annotation_args)
+                            self.assertTrue(is_instance)
+                        else:
+                            self.skipTest(f"Validating type {annotation} is unsupported.")