Jest mocks: added @reach/router and stub for Firebase auth signOut method

__mocks__/@reach/router.js

@@ -0,0 +1,17 @@
+import { delay } from '../../src/utils/index';
+
+const ReachRouter = jest.requireActual('@reach/router');
+
+const defaultDelayInMilliseconds = 100;
+
+// eslint-disable-next-line no-unused-vars
+const navigate = async (to, options) => {
+  await delay(defaultDelayInMilliseconds);
+
+  return Promise.resolve();
+};
+
+module.exports = {
+  ...ReachRouter,
+  navigate: jest.fn(navigate),
+};

__mocks__/gatsby-plugin-firebase/auth/auth.js

@@ -57,7 +57,7 @@ class Auth {
       user.email,
       user.isAnonymous,
       user.uid,
-      async () => {},
+      this.signOut,
     );
 
     await delay(Constants.defaultDelayInMilliseconds);
@@ -68,6 +68,20 @@ class Auth {
 
     return this._currentUser;
   }
+
+  async signOut() {
+    if (this._currentUser === null) {
+      return;
+    }
+
+    this._currentUser = null;
+
+    await delay(Constants.defaultDelayInMilliseconds);
+
+    this.onAuthStateChangedObservers.forEach((observer) =>
+      observer(this._currentUser),
+    );
+  }
 }
 
 export default Auth;

__mocks__/gatsby-plugin-firebase/constants/functions.js

@@ -1,6 +1,6 @@
 const deleteUserFunctionName = 'deleteUser';
 
-const defaultDelayInMilliseconds = 2000;
+const defaultDelayInMilliseconds = 100;
 
 class Functions {
   static get deleteUserFunctionName() {