diff --git a/tests/test-sources/plugins/completion/cmp-all-sources.nix b/tests/test-sources/plugins/completion/cmp-all-sources.nix
index f3690324..5de73d5c 100644
--- a/tests/test-sources/plugins/completion/cmp-all-sources.nix
+++ b/tests/test-sources/plugins/completion/cmp-all-sources.nix
@@ -20,6 +20,8 @@
                 disabledSources = [
                   # We do not provide the required HF_API_KEY environment variable.
                   "cmp_ai"
+                  # Triggers the warning complaining about treesitter highlighting being disabled
+                  "otter"
                 ] ++ optional (pkgs.stdenv.hostPlatform.system == "aarch64-linux") "cmp_tabnine";
               in
               pipe config.cmpSourcePlugins [