- 1. API with NestJS #1. Controllers, routing and the module structure
- 2. API with NestJS #2. Setting up a PostgreSQL database with TypeORM
- 3. API with NestJS #3. Authenticating users with bcrypt, Passport, JWT, and cookies
- 4. API with NestJS #4. Error handling and data validation
- 5. API with NestJS #5. Serializing the response with interceptors
- 6. API with NestJS #6. Looking into dependency injection and modules
- 7. API with NestJS #7. Creating relationships with Postgres and TypeORM
- 8. API with NestJS #8. Writing unit tests
- 9. API with NestJS #9. Testing services and controllers with integration tests
- 10. API with NestJS #10. Uploading public files to Amazon S3
- 11. API with NestJS #11. Managing private files with Amazon S3
- 12. API with NestJS #12. Introduction to Elasticsearch
- 13. API with NestJS #13. Implementing refresh tokens using JWT
- 14. API with NestJS #14. Improving performance of our Postgres database with indexes
- 15. API with NestJS #15. Defining transactions with PostgreSQL and TypeORM
- 16. API with NestJS #16. Using the array data type with PostgreSQL and TypeORM
- 17. API with NestJS #17. Offset and keyset pagination with PostgreSQL and TypeORM
- 18. API with NestJS #18. Exploring the idea of microservices
- 19. API with NestJS #19. Using RabbitMQ to communicate with microservices
- 20. API with NestJS #20. Communicating with microservices using the gRPC framework
- 21. API with NestJS #21. An introduction to CQRS
- 22. API with NestJS #22. Storing JSON with PostgreSQL and TypeORM
- 23. API with NestJS #23. Implementing in-memory cache to increase the performance
- 24. API with NestJS #24. Cache with Redis. Running the app in a Node.js cluster
- 25. API with NestJS #25. Sending scheduled emails with cron and Nodemailer
- 26. API with NestJS #26. Real-time chat with WebSockets
- 27. API with NestJS #27. Introduction to GraphQL. Queries, mutations, and authentication
- 28. API with NestJS #28. Dealing in the N + 1 problem in GraphQL
- 29. API with NestJS #29. Real-time updates with GraphQL subscriptions
- 30. API with NestJS #30. Scalar types in GraphQL
- 31. API with NestJS #31. Two-factor authentication
- 32. API with NestJS #32. Introduction to Prisma with PostgreSQL
- 33. API with NestJS #33. Managing PostgreSQL relationships with Prisma
- 34. API with NestJS #34. Handling CPU-intensive tasks with queues
- 35. API with NestJS #35. Using server-side sessions instead of JSON Web Tokens
- 36. API with NestJS #36. Introduction to Stripe with React
- 37. API with NestJS #37. Using Stripe to save credit cards for future use
- 38. API with NestJS #38. Setting up recurring payments via subscriptions with Stripe
- 39. API with NestJS #39. Reacting to Stripe events with webhooks
- 40. API with NestJS #40. Confirming the email address
- 41. API with NestJS #41. Verifying phone numbers and sending SMS messages with Twilio
- 42. API with NestJS #42. Authenticating users with Google
- 43. API with NestJS #43. Introduction to MongoDB
- 44. API with NestJS #44. Implementing relationships with MongoDB
- 45. API with NestJS #45. Virtual properties with MongoDB and Mongoose
- 46. API with NestJS #46. Managing transactions with MongoDB and Mongoose
- 47. API with NestJS #47. Implementing pagination with MongoDB and Mongoose
- 48. API with NestJS #48. Definining indexes with MongoDB and Mongoose
- 49. API with NestJS #49. Updating with PUT and PATCH with MongoDB and Mongoose
- 50. API with NestJS #50. Introduction to logging with the built-in logger and TypeORM
- 51. API with NestJS #51. Health checks with Terminus and Datadog
- 52. API with NestJS #52. Generating documentation with Compodoc and JSDoc
- 53. API with NestJS #53. Implementing soft deletes with PostgreSQL and TypeORM
- 54. API with NestJS #54. Storing files inside a PostgreSQL database
- 55. API with NestJS #55. Uploading files to the server
- 56. API with NestJS #56. Authorization with roles and claims
- 57. API with NestJS #57. Composing classes with the mixin pattern
- 58. API with NestJS #58. Using ETag to implement cache and save bandwidth
- 59. API with NestJS #59. Introduction to a monorepo with Lerna and Yarn workspaces
- 60. API with NestJS #60. The OpenAPI specification and Swagger
- 61. API with NestJS #61. Dealing with circular dependencies
- 62. API with NestJS #62. Introduction to MikroORM with PostgreSQL
- 63. API with NestJS #63. Relationships with PostgreSQL and MikroORM
- 64. API with NestJS #64. Transactions with PostgreSQL and MikroORM
- 65. API with NestJS #65. Implementing soft deletes using MikroORM and filters
- 66. API with NestJS #66. Improving PostgreSQL performance with indexes using MikroORM
- 67. API with NestJS #67. Migrating to TypeORM 0.3
- 68. API with NestJS #68. Interacting with the application through REPL
- 69. API with NestJS #69. Database migrations with TypeORM
- 70. API with NestJS #70. Defining dynamic modules
- 71. API with NestJS #71. Introduction to feature flags
- 72. API with NestJS #72. Working with PostgreSQL using raw SQL queries
- 73. API with NestJS #73. One-to-one relationships with raw SQL queries
- 74. API with NestJS #74. Designing many-to-one relationships using raw SQL queries
- 75. API with NestJS #75. Many-to-many relationships using raw SQL queries
- 76. API with NestJS #76. Working with transactions using raw SQL queries
- 77. API with NestJS #77. Offset and keyset pagination with raw SQL queries
- 78. API with NestJS #78. Generating statistics using aggregate functions in raw SQL
- 79. API with NestJS #79. Implementing searching with pattern matching and raw SQL
- 80. API with NestJS #80. Updating entities with PUT and PATCH using raw SQL queries
- 81. API with NestJS #81. Soft deletes with raw SQL queries
- 82. API with NestJS #82. Introduction to indexes with raw SQL queries
- 83. API with NestJS #83. Text search with tsvector and raw SQL
- 84. API with NestJS #84. Implementing filtering using subqueries with raw SQL
- 85. API with NestJS #85. Defining constraints with raw SQL
- 86. API with NestJS #86. Logging with the built-in logger when using raw SQL
- 87. API with NestJS #87. Writing unit tests in a project with raw SQL
- 88. API with NestJS #88. Testing a project with raw SQL using integration tests
- 89. API with NestJS #89. Replacing Express with Fastify
- 90. API with NestJS #90. Using various types of SQL joins
- 91. API with NestJS #91. Dockerizing a NestJS API with Docker Compose
- 92. API with NestJS #92. Increasing the developer experience with Docker Compose
- 93. API with NestJS #93. Deploying a NestJS app with Amazon ECS and RDS
- 94. API with NestJS #94. Deploying multiple instances on AWS with a load balancer
- 95. API with NestJS #95. CI/CD with Amazon ECS and GitHub Actions
- 96. API with NestJS #96. Running unit tests with CI/CD and GitHub Actions
- 97. API with NestJS #97. Introduction to managing logs with Amazon CloudWatch
- 98. API with NestJS #98. Health checks with Terminus and Amazon ECS
- 99. API with NestJS #99. Scaling the number of application instances with Amazon ECS
- 100. API with NestJS #100. The HTTPS protocol with Route 53 and AWS Certificate Manager
- 101. API with NestJS #101. Managing sensitive data using the AWS Secrets Manager
- 102. API with NestJS #102. Writing unit tests with Prisma
- 103. API with NestJS #103. Integration tests with Prisma
- 104. API with NestJS #104. Writing transactions with Prisma
- 105. API with NestJS #105. Implementing soft deletes with Prisma and middleware
- 106. API with NestJS #106. Improving performance through indexes with Prisma
- 107. API with NestJS #107. Offset and keyset pagination with Prisma
- 108. API with NestJS #108. Date and time with Prisma and PostgreSQL
- 109. API with NestJS #109. Arrays with PostgreSQL and Prisma
- 110. API with NestJS #110. Managing JSON data with PostgreSQL and Prisma
- 111. API with NestJS #111. Constraints with PostgreSQL and Prisma
- 112. API with NestJS #112. Serializing the response with Prisma
- 113. API with NestJS #113. Logging with Prisma
- 114. API with NestJS #114. Modifying data using PUT and PATCH methods with Prisma
- 115. API with NestJS #115. Database migrations with Prisma
- 116. API with NestJS #116. REST API versioning
- 117. API with NestJS #117. CORS – Cross-Origin Resource Sharing
- 118. API with NestJS #118. Uploading and streaming videos
- 119. API with NestJS #119. Type-safe SQL queries with Kysely and PostgreSQL
- 120. API with NestJS #120. One-to-one relationships with the Kysely query builder
- 121. API with NestJS #121. Many-to-one relationships with PostgreSQL and Kysely
- 122. API with NestJS #122. Many-to-many relationships with Kysely and PostgreSQL
- 123. API with NestJS #123. SQL transactions with Kysely
- 124. API with NestJS #124. Handling SQL constraints with Kysely
- 125. API with NestJS #125. Offset and keyset pagination with Kysely
- 126. API with NestJS #126. Improving the database performance with indexes and Kysely
- 127. API with NestJS #127. Arrays with PostgreSQL and Kysely
- 128. API with NestJS #128. Managing JSON data with PostgreSQL and Kysely
- 129. API with NestJS #129. Implementing soft deletes with SQL and Kysely
- 130. API with NestJS #130. Avoiding storing sensitive information in API logs
- 131. API with NestJS #131. Unit tests with PostgreSQL and Kysely
- 132. API with NestJS #132. Handling date and time in PostgreSQL with Kysely
- 133. API with NestJS #133. Introducing database normalization with PostgreSQL and Prisma
- 134. API with NestJS #134. Aggregating statistics with PostgreSQL and Prisma
- 135. API with NestJS #135. Referential actions and foreign keys in PostgreSQL with Prisma
- 136. API with NestJS #136. Raw SQL queries with Prisma and PostgreSQL range types
- 137. API with NestJS #137. Recursive relationships with Prisma and PostgreSQL
- 138. API with NestJS #138. Filtering records with Prisma
- 139. API with NestJS #139. Using UUID as primary keys with Prisma and PostgreSQL
- 140. API with NestJS #140. Using multiple PostgreSQL schemas with Prisma
- 141. API with NestJS #141. Getting distinct records with Prisma and PostgreSQL
- 142. API with NestJS #142. A video chat with WebRTC and React
- 143. API with NestJS #143. Optimizing queries with views using PostgreSQL and Kysely
- 144. API with NestJS #144. Creating CLI applications with the Nest Commander
- 145. API with NestJS #145. Securing applications with Helmet
- 146. API with NestJS #146. Polymorphic associations with PostgreSQL and Prisma
- 147. API with NestJS #147. The data types to store money with PostgreSQL and Prisma
- 148. API with NestJS #148. Understanding the injection scopes
- 149. API with NestJS #149. Introduction to the Drizzle ORM with PostgreSQL
- 150. API with NestJS #150. One-to-one relationships with the Drizzle ORM
- 151. API with NestJS #151. Implementing many-to-one relationships with Drizzle ORM
- 152. API with NestJS #152. SQL constraints with the Drizzle ORM
- 153. API with NestJS #153. SQL transactions with the Drizzle ORM
- 154. API with NestJS #154. Many-to-many relationships with Drizzle ORM and PostgreSQL
- 155. API with NestJS #155. Offset and keyset pagination with the Drizzle ORM
- 156. API with NestJS #156. Arrays with PostgreSQL and the Drizzle ORM
- 157. API with NestJS #157. Handling JSON data with PostgreSQL and the Drizzle ORM
- 158. API with NestJS #158. Soft deletes with the Drizzle ORM
- 159. API with NestJS #159. Date and time with PostgreSQL and the Drizzle ORM
- 160. API with NestJS #160. Using views with the Drizzle ORM and PostgreSQL
- 161. API with NestJS #161. Generated columns with the Drizzle ORM and PostgreSQL
- 162. API with NestJS #162. Identity columns with the Drizzle ORM and PostgreSQL
- 163. API with NestJS #163. Full-text search with the Drizzle ORM and PostgreSQL
- 164. API with NestJS #164. Improving the performance with indexes using Drizzle ORM
- 165. API with NestJS #165. Time intervals with the Drizzle ORM and PostgreSQL
- 166. API with NestJS #166. Logging with the Drizzle ORM
- 167. API with NestJS #167. Unit tests with the Drizzle ORM
- 168. API with NestJS #168. Integration tests with the Drizzle ORM
In the previous part of this series, we learned how to write unit tests in a NestJS project with Prisma. Unit tests help verify if individual components of our system work as expected on their own. However, while useful, they don’t guarantee that our API functions correctly as a whole. In this article, we deal with it by implementing integration tests.
You can find all of the code from this article in this repository.
Introducing integration tests
An integration test verifies if multiple parts of our application work together. We can do that by testing the integration of two or more pieces of our system.
Let’s investigate the getAuthenticatedUser method in our AuthenticationService.
authentication.service.ts
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import { BadRequestException, Injectable } from '@nestjs/common'; import { UsersService } from '../users/users.service'; import * as bcrypt from 'bcrypt'; import { UserNotFoundException } from '../users/exceptions/userNotFound.exception'; @Injectable() export class AuthenticationService { constructor(private readonly usersService: UsersService) {} public async getAuthenticatedUser(email: string, plainTextPassword: string) { try { const user = await this.usersService.getByEmail(email); await this.verifyPassword(plainTextPassword, user.password); return user; } catch (error) { if (error instanceof UserNotFoundException) { throw new BadRequestException(); } throw error; } } private async verifyPassword( plainTextPassword: string, hashedPassword: string, ) { const isPasswordMatching = await bcrypt.compare( plainTextPassword, hashedPassword, ); if (!isPasswordMatching) { throw new BadRequestException('Wrong credentials provided'); } } // ... } |
When we look closely, we can distinguish a few cases. The getAuthenticatedUser method:
- should throw an error if the user can’t be found,
- should throw an error if the provided password is not valid,
- should return the user if the user is found and the provided password is correct.
In the previous article, we tested the AuthenticationService in isolation and mocked the UsersService. This time, let’s test how they work together.
Even though we are writing an integration test, it does not necessarily mean we want to include every part of our system. For example, in this particular case, we still want to mock our PrismaService class to avoid making actual database calls.
authentication.service.test.ts
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import { AuthenticationService } from './authentication.service'; import { JwtModule } from '@nestjs/jwt'; import { ConfigModule } from '@nestjs/config'; import { Test } from '@nestjs/testing'; import { PrismaService } from '../prisma/prisma.service'; import { UsersService } from '../users/users.service'; describe('The AuthenticationService', () => { let authenticationService: AuthenticationService; let password: string; let findUniqueMock: jest.Mock; beforeEach(async () => { password = 'strongPassword123'; findUniqueMock = jest.fn(); const module = await Test.createTestingModule({ providers: [ AuthenticationService, UsersService, { provide: PrismaService, useValue: { user: { findUnique: findUniqueMock, }, }, }, ], imports: [ ConfigModule.forRoot(), JwtModule.register({ secretOrPrivateKey: 'Secret key', }), ], }).compile(); authenticationService = await module.get(AuthenticationService); }); // ... }); |
First, we provide a Jest function in our PrismaService mock to be able to change the implementation per test.
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{ provide: PrismaService, useValue: { user: { findUnique: findUniqueMock, }, }, }, |
By doing that, we can alter the findUnique method to cover all of the cases:
- the prismaService.user.findUnique method returns the requested user,
- the prismaService.user.findUnique method does not find the user.
authentication.service.test.ts
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import { User } from '@prisma/client'; import { BadRequestException } from '@nestjs/common'; import * as bcrypt from 'bcrypt'; describe('The AuthenticationService', () => { // ... describe('when the getAuthenticatedUser method is called', () => { describe('and the user can be found in the database', () => { let user: User; beforeEach(async () => { const hashedPassword = await bcrypt.hash(password, 10); user = { id: 1, email: 'john@smith.com', name: 'John', password: hashedPassword, addressId: null, }; findUniqueMock.mockResolvedValue(user); }); describe('and a correct password is provided', () => { it('should return the new user', async () => { const result = await authenticationService.getAuthenticatedUser( user.email, password, ); expect(result).toBe(user); }); }); describe('and an incorrect password is provided', () => { it('should throw the BadRequestException', () => { return expect(async () => { await authenticationService.getAuthenticatedUser( 'john@smith.com', 'wrongPassword', ); }).rejects.toThrow(BadRequestException); }); }); }); describe('and the user can not be found in the database', () => { beforeEach(() => { findUniqueMock.mockResolvedValue(undefined); }); it('should throw the BadRequestException', () => { return expect(async () => { await authenticationService.getAuthenticatedUser( 'john@smith.com', password, ); }).rejects.toThrow(BadRequestException); }); }); }); }); |
The AuthenticationService
when the getAuthenticatedUser method is called
and the user can be found in the database
and a correct password is provided
✓ should return the new user
and an incorrect password is provided
✓ should throw the BadRequestException
and the user can not be found in the database
✓ should throw the BadRequestException
By not mocking the UsersService in the above tests, we ensured that it integrates as expected with the AuthenticationService. Whenever we call the authenticationService.getAuthenticatedUser method in our test, it uses the actual usersService.getByEmail method under the hood.
Testing controllers using API calls
Another approach we could take to our integration testing is to perform HTTP requests to our API. This allows us to test multiple application layers, starting with the controllers.
To perform the tests, we need the SuperTest library.
1 |
npm install supertest @types/supertest |
Let’s start by testing the most basic case with registering the new user.
authentication.controller.test.ts
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import { AuthenticationService } from './authentication.service'; import { JwtModule } from '@nestjs/jwt'; import { ConfigModule } from '@nestjs/config'; import { Test } from '@nestjs/testing'; import { User } from '@prisma/client'; import { PrismaService } from '../prisma/prisma.service'; import { UsersService } from '../users/users.service'; import { INestApplication } from '@nestjs/common'; import * as request from 'supertest'; import { AuthenticationController } from './authentication.controller'; describe('The AuthenticationController', () => { let createUserMock: jest.Mock; let app: INestApplication; beforeEach(async () => { createUserMock = jest.fn(); const module = await Test.createTestingModule({ providers: [ AuthenticationService, UsersService, { provide: PrismaService, useValue: { user: { create: createUserMock, }, }, }, ], controllers: [AuthenticationController], imports: [ ConfigModule.forRoot(), JwtModule.register({ secretOrPrivateKey: 'Secret key', }), ], }).compile(); app = module.createNestApplication(); await app.init(); }); describe('when the register endpoint is called', () => { describe('and valid data is provided', () => { let user: User; beforeEach(async () => { user = { id: 1, email: 'john@smith.com', name: 'John', password: 'strongPassword', addressId: null, }; }); describe('and the user is successfully created in the database', () => { beforeEach(() => { createUserMock.mockResolvedValue(user); }); it('should return the new user without the password', async () => { return request(app.getHttpServer()) .post('/authentication/register') .send({ email: user.email, name: user.name, password: user.password, }) .expect({ id: user.id, name: user.name, email: user.email, addressId: null, }); }); }); }); }); }); |
The AuthenticationController
when the register endpoint is called
and valid data is provided
and the user is successfully created in the database
✓ should return the new user without the password
In the above code, we create a testing module that includes the AuthenticationController. This way, we can make an HTTP request to the /register endpoint.
Besides the most basic case, we can also test what happens if the email is already taken. To do that, we must ensure our mocked method throws the PrismaClientKnownRequestError.
authentication.controller.test.ts
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import { Prisma, User } from '@prisma/client'; import { INestApplication } from '@nestjs/common'; import * as request from 'supertest'; import { PrismaError } from '../utils/prismaError'; describe('The AuthenticationController', () => { let createUserMock: jest.Mock; let app: INestApplication; // ... describe('when the register endpoint is called', () => { describe('and valid data is provided', () => { let user: User; beforeEach(async () => { user = { id: 1, email: 'john@smith.com', name: 'John', password: 'strongPassword', addressId: null, }; }); // ... describe('and the email is already taken', () => { beforeEach(async () => { createUserMock.mockImplementation(() => { throw new Prisma.PrismaClientKnownRequestError( 'The user already exists', { code: PrismaError.UniqueConstraintFailed, clientVersion: '4.12.0', }, ); }); }); it('should result in 400 Bad Request', async () => { return request(app.getHttpServer()) .post('/authentication/register') .send({ email: user.email, name: user.name, password: user.password, }) .expect(400); }); }); }); }); }); |
The AuthenticationController
when the register endpoint is called
and valid data is provided
and the user is successfully created in the database
✓ should return the new user without the password
and the email is already taken
✓ should result in 400 Bad Request
Testing the validation
Our NestJS application validates the data sent when making POST requests. For example, we check if the provided registration data contains a valid email, name, and password.
register.dto.ts
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import { IsString, IsNotEmpty, IsEmail } from 'class-validator'; class RegisterDto { @IsString() @IsNotEmpty() @IsEmail() email: string; @IsString() @IsNotEmpty() name: string; @IsString() @IsNotEmpty() password: string; } export default RegisterDto; |
When testing the above, it is crucial to attach the ValidationPipe to our testing module.
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import { AuthenticationService } from './authentication.service'; import { JwtModule } from '@nestjs/jwt'; import { ConfigModule } from '@nestjs/config'; import { Test } from '@nestjs/testing'; import { PrismaService } from '../prisma/prisma.service'; import { UsersService } from '../users/users.service'; import { INestApplication, ValidationPipe } from '@nestjs/common'; import * as request from 'supertest'; import { AuthenticationController } from './authentication.controller'; describe('The AuthenticationController', () => { let createUserMock: jest.Mock; let app: INestApplication; beforeEach(async () => { createUserMock = jest.fn(); const module = await Test.createTestingModule({ providers: [ AuthenticationService, UsersService, { provide: PrismaService, useValue: { user: { create: createUserMock, }, }, }, ], controllers: [AuthenticationController], imports: [ ConfigModule.forRoot(), JwtModule.register({ secretOrPrivateKey: 'Secret key', }), ], }).compile(); app = module.createNestApplication(); app.useGlobalPipes(new ValidationPipe({ transform: true })); await app.init(); }); describe('when the register endpoint is called', () => { // ... describe('and the email is missing', () => { it('should result in 400 Bad Request', async () => { return request(app.getHttpServer()) .post('/authentication/register') .send({ name: 'John', password: 'strongPassword', }) .expect(400); }); }); }); }); |
The AuthenticationController
when the register endpoint is called
and valid data is provided
and the user is successfully created in the database
✓ should return the new user without the password
and the email is already taken
✓ should result in 400 Bad Request
and the email is missing
✓ should result in 400 Bad Request
Summary
In this article, we’ve gone through the idea of writing integration tests. As an example, we’ve used a NestJS application using Prisma. When doing so, we had to learn how to mock Prisma properly, including throwing errors. All of the above will definitely help us ensure that our app works as expected.