Fix unittests

Author: ZeJ0hn

test/components/fetchers/test_link_content_fetcher.py

@@ -178,9 +178,9 @@ def test_request_headers_merging_and_ua_override(self):
 
             client.get.assert_called_once()
             sent_headers = client.get.call_args.kwargs["headers"]
-            assert sent_headers["X-Test"] == "1"
-            assert sent_headers["Accept-Language"] == "fr-FR"
-            assert sent_headers["User-Agent"] == "ua-sync-1"  # rotating UA wins
+            assert sent_headers["x-test"] == "1"
+            assert sent_headers["accept-language"] == "fr-FR"
+            assert sent_headers["user-agent"] == "ua-sync-1"  # rotating UA wins
 
     @pytest.mark.integration
     def test_link_content_fetcher_html(self):