tests: adding sphinx-todo extension directives test

Adding a test to validate the expected use of Sphinx's todo directives.
This includes ensuring they only render when enabled, as well as
ensuring an informational block is created when they are enabled.

Signed-off-by: James Knight <james.d.knight@live.com>

tests/unit-tests/datasets/todo/index.rst

@@ -0,0 +1,8 @@
+.. https://www.sphinx-doc.org/en/master/usage/extensions/todo.html
+
+todo
+----
+
+.. todo::
+
+    example message

tests/unit-tests/test_sphinx_todo.py

@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: BSD-2-Clause
+# Copyright Sphinx Confluence Builder Contributors (AUTHORS)
+
+from tests.lib.parse import parse
+from tests.lib.testcase import ConfluenceTestCase
+from tests.lib.testcase import setup_builder
+
+
+class TestConfluenceSphinxTodo(ConfluenceTestCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+
+        cls.config['extensions'].append('sphinx.ext.todo')
+        cls.dataset = cls.datasets / 'todo'
+
+    @setup_builder('confluence')
+    def test_storage_sphinx_todo_default(self):
+        out_dir = self.build(self.dataset)
+
+        with parse('index', out_dir) as data:
+            info_macros = data.find_all('ac:structured-macro',
+                {'ac:name': 'info'})
+            self.assertEqual(len(info_macros), 0)
+
+    @setup_builder('confluence')
+    def test_storage_sphinx_todo_enabled(self):
+        config = dict(self.config)
+        config['todo_include_todos'] = True
+
+        out_dir = self.build(self.dataset, config=config)
+
+        with parse('index', out_dir) as data:
+            info_macros = data.find_all('ac:structured-macro',
+                {'ac:name': 'info'})
+            self.assertEqual(len(info_macros), 1)
+
+            info_macro = info_macros.pop(0)
+
+            info_macro_title = info_macro.find('ac:parameter',
+                {'ac:name': 'title'})
+            self.assertIsNotNone(info_macro_title)
+
+            rich_body = info_macro.find('ac:rich-text-body')
+            self.assertIsNotNone(rich_body)
+
+            text_contents = rich_body.text.strip()
+            self.assertIsNotNone(text_contents)
+            self.assertTrue('example message' in text_contents)