allow overriding the "incorporeal.org" in <title>

I'm not going to be able to use this software on incorporeal.org for a
bit, so plan B

tests/test_factory.py

@@ -11,3 +11,13 @@ def test_config():
     instance_path = os.path.join(HERE, 'instance')
     assert not create_app(instance_path=instance_path).testing
     assert create_app(instance_path=instance_path, test_config={"TESTING": True}).testing
+
+
+def test_title_override():
+    """Test that a configuration with a specific title overrides the default."""
+    instance_path = os.path.join(HERE, 'instance')
+    app = create_app(instance_path=instance_path, test_config={'TITLE_SUFFIX': 'suou.net'})
+    client = app.test_client()
+    response = client.get('/no-title')
+    assert response.status_code == 200
+    assert b'<title>suou.net</title>' in response.data