diff --git a/tests/unit/AppHeader.spec.js b/tests/unit/AppHeader.spec.js
index ed78f03..2d17e76 100644
--- a/tests/unit/AppHeader.spec.js
+++ b/tests/unit/AppHeader.spec.js
@@ -16,7 +16,15 @@
     'global/getSystemInfo': jest.fn(),
   };
 
-  const store = new Vuex.Store({ actions });
+  // VueX requires that all modules be present, even if they aren't used
+  // in the test, so invent a Fake auth module and install it.
+  const modules = {
+    authentication: {
+      namespaced: true,
+    },
+  };
+
+  const store = new Vuex.Store({ actions, modules });
   const wrapper = mount(AppHeader, {
     store,
     localVue,