TypeError: firebase__default.default.initializeApp is not a function when using initializeTestApp method

Environment

node: 14.15.5
OS: macOS Big Sur v11.2

What is the problem

When I try to run test with Jest, test fails with an error message that "TypeError: firebase__default.default.initializeApp is not a function" even if I use initializeTestApp, not initializeApp

What I have tried

• I used @firebase/rules-unit-testing ver2.0.0 but there was no initializeTestApp function so I downgraded the version to 1.3.14 as described below.
• I deleted yarn.lock file and use command yarn install but it did not work.
• I searched issues but there is no exact the same issue.(this is similar issue: https://github.com/firebase/firebase-js-sdk/issues/4944)

I would really appreciate if you can give me any advices. Thank you.

firebaseRules.test.ts

import * as firebase from "@firebase/rules-unit-testing"; import fs from "fs"; import path from "path"; const myId = "user_Id"; // Load security rules const filePath = path.join(__dirname, "./firestore.rules"); const rules = fs.readFileSync(filePath, "utf8"); const myProjectId = "my-project-2021"; describe("Allow access to users collection only when user is authorized", () => { beforeEach( async () => await firebase.clearFirestoreData({ projectId: myProjectId }) ); beforeEach( async () => await firebase.loadFirestoreRules({ projectId: myProjectId, rules: rules, }) ); afterAll( async () => await firebase.clearFirestoreData({ projectId: myProjectId }) ); describe("allow access to project collection only when user is authorized", () => { test("fail to access without auth", async () => { const db = firebase // here test fails: TypeError: firebase__default.default.initializeApp is not a function .initializeTestApp({ projectId: myProjectId, }) .firestore(); const doc = db .collection("users") .doc("user_shogo") .collection("projects") .doc("testProjectId"); await firebase.assertFails(doc.get()); }); }); }); 

package.json

{ "name": "move-gantt", "version": "0.1.0", "private": true, "scripts": { "dev": "next dev", "build": "next build", "start": "next start", "lint": "next lint", "test": "jest --silent=false --verbose false" }, "dependencies": { "@firebase/rules-unit-testing": "1.3.14", "@material-ui/core": "^4.12.3", "@material-ui/icons": "^5.0.0-beta.4", "@material-ui/lab": "^4.0.0-alpha.60", "@material-ui/styles": "^4.11.4", "@types/react-redux": "^7.1.18", "date-fns": "^2.23.0", "firebase": "8.10.0", "firebase-tools": "^9.16.6", "next": "11.0.1", "next-transpile-modules": "^8.0.0", "react": "17.0.2", "react-dom": "17.0.2", "react-redux": "^7.2.4", "redux": "^4.1.1", "redux-devtools-extension": "^2.13.9", "redux-logger": "^3.0.6", "styled-components": "^5.3.0", "styled-jsx": "3.4.5" }, "devDependencies": { "@babel/cli": "^7.14.8", "@babel/core": "^7.15.0", "@testing-library/react": "^12.0.0", "@types/jest": "^27.0.0", "@types/node": "^16.4.11", "@types/react": "^17.0.15", "@types/react-dom": "^17.0.9", "@types/react-test-renderer": "^17.0.1", "@types/redux-logger": "^3.0.9", "@types/styled-components": "^5.1.11", "babel-plugin-styled-components": "^1.13.2", "eslint": "7.32.0", "eslint-config-next": "11.0.1", "firebase-admin": "9.8.0", "jest": "^27.0.6", "react-test-renderer": "^17.0.2", "ts-jest": "^27.0.4", "typescript": "^4.3.5" } }