Add S3CacheService tests

apps/api/src/s3-cache/s3-cache.service.spec.ts

@@ -0,0 +1,71 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { S3CacheService, S3_CACHE_REDIS_PREFIX } from './s3-cache.service';
+import { S3Service } from '../s3/s3.service';
+import { RedisService } from '../redis/redis.service';
+import { Readable } from 'stream';
+import Utils from '../helpers/utils';
+import Redis from 'ioredis-mock';
+
+describe('S3CacheService', () => {
+	let service: S3CacheService;
+
+	const s3ServiceMock = {
+		getObjectBody: jest.fn(() => Readable.from(Buffer.from('object'))),
+	};
+
+	const redisMock = new Redis();
+	const redisService = {
+		client: redisMock,
+	};
+
+	const getObjectBodyMock = jest.spyOn(s3ServiceMock, 'getObjectBody');
+	const redisSetSpy = jest.spyOn(redisService.client, 'set');
+
+	beforeEach(async () => {
+		const module: TestingModule = await Test.createTestingModule({
+			providers: [
+				S3CacheService,
+				{
+					provide: S3Service,
+					useValue: s3ServiceMock,
+				},
+				{
+					provide: RedisService,
+					useValue: redisService,
+				},
+			],
+		}).compile();
+		service = module.get<S3CacheService>(S3CacheService);
+	});
+
+	afterAll(() => {
+		jest.clearAllMocks();
+		redisService.client.flushall();
+	});
+
+	it('should be defined', () => {
+		expect(service).toBeDefined();
+	});
+
+	it('should get object if cached', async () => {
+		const mockObject = Buffer.from('object');
+		redisService.client.set(generateRedisKey('old-key'), mockObject);
+
+		const object = await service.getObject('old-key');
+
+		expect(Utils.streamToBuffer(object)).resolves.toEqual(mockObject);
+		expect(getObjectBodyMock).toHaveBeenCalledTimes(0);
+	});
+
+	it('should get and store object if not cached', async () => {
+		const object = await service.getObject('new-key');
+
+		expect(Utils.streamToBuffer(object)).resolves.toEqual(Buffer.from('object'));
+		expect(getObjectBodyMock).toHaveBeenCalledWith('new-key');
+		expect(redisSetSpy).toHaveBeenCalledWith(generateRedisKey('new-key'), Buffer.from('object'));
+	});
+
+	function generateRedisKey(key: string) {
+		return `${S3_CACHE_REDIS_PREFIX}${key}`;
+	}
+});