I am tryng to code a test for upload.
But i am not understating how to properly use jest.mock('aws-sdk')
export class S3Service {
private readonly s3: S3;
private readonly bucket: string;
constructor(private readonly configService: ConfigService) {
this.s3 = new S3({
accessKeyId: this.configService.get(''),
secretAccessKey: this.configService.get(''),
region: this.configService.get(''),
});
this.bucket = this.configService.get('');
}
async upload(name: string, contentType: string, buffer: Buffer): Promise<string> {
const upload = await this.s3.upload({params...}).promise();
return upload;
}
}
Here is the unit test solution:
s3Service.ts
:
import { S3 } from 'aws-sdk';
export class S3Service {
private readonly s3: S3;
private readonly bucket: string;
constructor(private readonly configService) {
this.s3 = new S3({
accessKeyId: this.configService.get(''),
secretAccessKey: this.configService.get(''),
region: this.configService.get(''),
});
this.bucket = this.configService.get('');
}
public async upload(name: string, contentType: string, buffer: Buffer): Promise<any> {
const bucket = this.bucket;
const params = { Bucket: bucket, Key: 'key', Body: buffer };
const upload = await this.s3.upload(params).promise();
return upload;
}
}
s3Service.test.ts
:
import { S3Service } from './s3Service';
const mS3Instance = {
upload: jest.fn().mockReturnThis(),
promise: jest.fn(),
};
jest.mock('aws-sdk', () => {
return { S3: jest.fn(() => mS3Instance) };
});
describe('61830632', () => {
it('should upload correctly', async () => {
const configService = {
get: jest
.fn()
.mockReturnValueOnce('accessKeyId')
.mockReturnValueOnce('secretAccessKey')
.mockReturnValueOnce('us-east')
.mockReturnValueOnce('bucket-dev'),
};
mS3Instance.promise.mockResolvedValueOnce('fake response');
const s3Service = new S3Service(configService);
const actual = await s3Service.upload('name', 'contentType', Buffer.from('ok'));
expect(actual).toEqual('fake response');
expect(mS3Instance.upload).toBeCalledWith({ Bucket: 'bucket-dev', Key: 'key', Body: Buffer.from('ok') });
});
});
unit test results with 100% coverage:
PASS stackoverflow/61830632/s3Service.test.ts (11.362s)
61830632
✓ should upload correctly (6ms)
--------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
--------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
s3Service.ts | 100 | 100 | 100 | 100 |
--------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 12.738s