diff --git a/tests/modules/programs/firefox/profiles/extensions/default.nix b/tests/modules/programs/firefox/profiles/extensions/default.nix
index b58a7c3ef..902c17349 100644
--- a/tests/modules/programs/firefox/profiles/extensions/default.nix
+++ b/tests/modules/programs/firefox/profiles/extensions/default.nix
@@ -34,6 +34,10 @@ in
         assertFileContent \
           "home-files/${cfg.profilesPath}/extensions/browser-extension-data/uBlock0@raymondhill.net/storage.js" \
           ${./expected-storage.js}
+
+        assertFileContent \
+          "home-files/${cfg.profilesPath}/extensions/user.js" \
+          ${./expected-user.js}
       '';
     }
   );
diff --git a/tests/modules/programs/firefox/profiles/extensions/expected-user.js b/tests/modules/programs/firefox/profiles/extensions/expected-user.js
new file mode 100644
index 000000000..8e77e9cc6
--- /dev/null
+++ b/tests/modules/programs/firefox/profiles/extensions/expected-user.js
@@ -0,0 +1,8 @@
+// Generated by Home Manager.
+
+
+
+user_pref("extensions.webextensions.ExtensionStorageIDB.enabled", false);
+
+
+