diff --git a/src/authSlice.js b/src/authSlice.js
index 1da67ea..63f9f6b 100644
--- a/src/authSlice.js
+++ b/src/authSlice.js
@@ -77,7 +77,7 @@ export function requestGoogleSignIn() {
   return async (dispatch) => {
     try {
       dispatch(setIsLoading(true));
-      const { user } = await postGoogleSignIn();
+      const user = await postGoogleSignIn();
       const { email, displayName, uid } = user;
 
       dispatch(setUser({ email, displayName, uid }));
diff --git a/src/authSlice.test.js b/src/authSlice.test.js
index e4add60..7f1fb42 100644
--- a/src/authSlice.test.js
+++ b/src/authSlice.test.js
@@ -133,9 +133,7 @@ describe('actions', () => {
 
     context('when request success', () => {
       it('returns user and change url path', async () => {
-        postGoogleSignIn.mockImplementationOnce(() => ({
-          user: logInUser,
-        }));
+        postGoogleSignIn.mockImplementationOnce(() => logInUser);
 
         await store.dispatch(requestGoogleSignIn());
 
diff --git a/src/services/__mocks__/firebase.js b/src/services/__mocks__/firebase.js
index c90211c..582f413 100644
--- a/src/services/__mocks__/firebase.js
+++ b/src/services/__mocks__/firebase.js
@@ -1,9 +1,14 @@
 import products from '../../../fixtures/products';
+import { logInUser } from '../../../fixtures/user';
 
 const collections = {
   products,
 };
 
+const googleAuthLogin = jest.fn().mockImplementation(() => ({
+  user: logInUser,
+}));
+
 const firebase = {
   auth: jest.fn(() => ({
     signInWithEmailAndPassword: jest.fn((email, password) => ({
@@ -34,7 +39,7 @@ const firebase = {
         delete: jest.fn(),
       })),
       add: jest.fn().mockImplementation((item) => item),
-      where: jest.fn().mockImplementation((fieldName, operator, value) => {
+      where: jest.fn().mockImplementation((_, operator, value) => {
         let result = null;
 
         if (operator === '==') {
@@ -54,10 +59,17 @@ const firebase = {
     })),
   })),
   storage: jest.fn().mockImplementation(() => ({
-    refFromURL: jest.fn().mockImplementation((url) => ({
+    refFromURL: jest.fn().mockImplementation(() => ({
       delete: jest.fn(),
     })),
+    ref: jest.fn(() => ({
+      child: jest.fn(() => ({
+        put: jest.fn(),
+        getDownloadURL: jest.fn(() => 'MOCK_IMAGE_URL'),
+      })),
+    })),
   })),
 };
 
 export default firebase;
+export { googleAuthLogin };
diff --git a/src/services/api.js b/src/services/api.js
index 7b913b0..ed592dd 100644
--- a/src/services/api.js
+++ b/src/services/api.js
@@ -1,5 +1,5 @@
 import { v4 as uuidv4 } from 'uuid';
-import firebase from './firebase';
+import firebase, { googleAuthLogin } from './firebase';
 import { isEmpty } from '../utils';
 
 export async function fetchProducts() {
@@ -43,10 +43,10 @@ export async function fetchUserProducts({ user }) {
 
 export async function uploadProductImages({ files }) {
   async function uploadProductImage(file) {
-    const uploadTask = firebase.storage()
+    const reference = firebase.storage()
       .ref().child(`${file.name}${uuidv4()}`);
-    const response = await uploadTask.put(file);
-    const imageUrl = await response.ref.getDownloadURL();
+    await reference.put(file);
+    const imageUrl = await reference.getDownloadURL();
     return imageUrl;
   }
 
@@ -89,7 +89,7 @@ export async function postDeleteProduct({ product }) {
   await firebase
     .firestore().collection('products').doc(id).delete();
 
-  if (isEmpty(productImages || [])) {
+  if (isEmpty(productImages)) {
     return;
   }
 
@@ -106,10 +106,9 @@ export async function postLogin({ email, password }) {
 }
 
 export async function postGoogleSignIn() {
-  const provider = new firebase.auth.GoogleAuthProvider();
-  const response = await firebase.auth().signInWithPopup(provider);
+  const { user } = await googleAuthLogin();
 
-  return response;
+  return user;
 }
 
 export async function postSignup({ email, password }) {
diff --git a/src/services/api.test.js b/src/services/api.test.js
index 9c27292..970419e 100644
--- a/src/services/api.test.js
+++ b/src/services/api.test.js
@@ -9,6 +9,8 @@ import {
   postLogin,
   postSignup,
   postLogout,
+  uploadProductImages,
+  postGoogleSignIn,
 } from './api';
 
 import products, { userProducts } from '../../fixtures/products';
@@ -56,6 +58,31 @@ describe('api', () => {
     });
   });
 
+  describe('uploadProductImages', () => {
+    it('returns productImages', async () => {
+      const files = [
+        new File(['file'], 'productImage1.png', {
+          type: 'application/json',
+        }),
+        new File(['file'], 'productImage2.png', {
+          type: 'application/json',
+        }),
+        new File(['file'], 'productImage3.png', {
+          type: 'application/json',
+        }),
+      ];
+
+      const data = await uploadProductImages({ files });
+
+      const productImages = files.map((file, _) => ({
+        name: file.name,
+        imageUrl: 'MOCK_IMAGE_URL',
+      }));
+
+      expect(data).toEqual(productImages);
+    });
+  });
+
   describe('postEditProduct', () => {
     it('request product post edit', async () => {
       const productId = 1;
@@ -83,12 +110,13 @@ describe('api', () => {
     });
 
     context('productImages is empty', () => {
-      it('request only product pos delete', async () => {
-        const emptyImagesProductPost = {
+      it('request only post delete', async () => {
+        const emptyImagesInPost = {
           ...product,
           productImages: [],
         };
-        await postDeleteProduct({ product: emptyImagesProductPost });
+
+        await postDeleteProduct({ product: emptyImagesInPost });
       });
     });
   });
@@ -108,6 +136,14 @@ describe('api', () => {
     });
   });
 
+  describe('postGoogleSignin', () => {
+    it('returns user', async () => {
+      const data = await postGoogleSignIn();
+
+      expect(data).toEqual(logInUser);
+    });
+  });
+
   describe('postSignup', () => {
     it('returns sign up user', async () => {
       const email = 'ghdrlfehd@test.com';
diff --git a/src/services/firebase.js b/src/services/firebase.js
index 514156d..6a495ee 100644
--- a/src/services/firebase.js
+++ b/src/services/firebase.js
@@ -15,4 +15,7 @@ const firebaseConfig = {
 
 firebase.initializeApp(firebaseConfig);
 
+const googleAuthProvider = new firebase.auth.GoogleAuthProvider();
+export const googleAuthLogin = () => firebase.auth().signInWithPopup(googleAuthProvider);
+
 export default firebase;