- 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
Testing our application can increase our confidence when it comes to creating a fully-functional API. In this article, we look into how we can test our application by writing unit tests. We do so by using some of the utilities built into NestJS, as well as the Jest library.
If you would like to get to know Jest better first, check out the first part of the JavaScript testing tutorial.
Testing NestJS with unit tests
The job of a unit test is to verify an individual piece of code. A tested unit can be a module, a class, or a function. Each of our tests should be isolated and independent of each other. By writing unit tests, we can make sure that individual parts of our application work as expected.
Let’s write some tests for the AuthenticationService.
src/authentication/tests/authentication.service.spec.ts
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import { AuthenticationService } from '../authentication.service'; import { UsersService } from '../../users/users.service'; import { Repository } from 'typeorm'; import User from '../../users/user.entity'; import { JwtService } from '@nestjs/jwt'; import { ConfigService } from '@nestjs/config'; describe('The AuthenticationService', () => { const authenticationService = new AuthenticationService( new UsersService( new Repository<User>() ), new JwtService({ secretOrPrivateKey: 'Secret key' }), new ConfigService() ); describe('when creating a cookie', () => { it('should return a string', () => { const userId = 1; expect( typeof authenticationService.getCookieWithJwtToken(userId) ).toEqual('string') }) }) }); |
PASS src/authentication/tests/authentication.service.spec.ts
The AuthenticationService
when creating a cookie
✓ should return a string (12ms)
When we execute npm run test, Jest looks for files ending with .spec.ts and executes them.
We can improve the above code. Each of our tests needs to be independent, and we need to ensure that. If we add more tests in the above file, all of them will use the same instance of the AuthenticationService. It breaks the rule of all tests being independent.
To deal with it, we can use the beforeEach that runs before every test.
src/authentication/tests/authentication.service.spec.ts
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import { AuthenticationService } from '../authentication.service'; import { UsersService } from '../../users/users.service'; import { Repository } from 'typeorm'; import User from '../../users/user.entity'; import { JwtService } from '@nestjs/jwt'; import { ConfigService } from '@nestjs/config'; describe('The AuthenticationService', () => { let authenticationService: AuthenticationService; beforeEach(() => { authenticationService = new AuthenticationService( new UsersService( new Repository<User>() ), new JwtService({ secretOrPrivateKey: 'Secret key' }), new ConfigService() ); }) describe('when creating a cookie', () => { it('should return a string', () => { const userId = 1; expect( typeof authenticationService.getCookieWithJwtToken(userId) ).toEqual('string') }) }) }); |
Now, we are sure that every test in the authentication.service.spec.ts file gets a brand new instance of the AuthenticationService.
Unfortunately, the above code does not look very elegant. Because the constructor of the AuthenticationService expects some dependencies, we provided them manually so far.
Creating testing modules
Fortunately, NestJS provides us with built-in utilities to deal with the above issue.
1 |
npm install @nestjs/testing |
By using Test.createTestingModule().compile() we can create a module with its dependencies resolved.
src/authentication/tests/authentication.service.spec.ts
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import { AuthenticationService } from '../authentication.service'; import { Test } from '@nestjs/testing'; import { UsersModule } from '../../users/users.module'; import { ConfigModule, ConfigService } from '@nestjs/config'; import { JwtModule } from '@nestjs/jwt'; import { DatabaseModule } from '../../database/database.module'; import * as Joi from '@hapi/joi'; describe('The AuthenticationService', () => { let authenticationService: AuthenticationService; beforeEach(async () => { const module = await Test.createTestingModule({ imports: [ UsersModule, ConfigModule.forRoot({ validationSchema: Joi.object({ POSTGRES_HOST: Joi.string().required(), POSTGRES_PORT: Joi.number().required(), POSTGRES_USER: Joi.string().required(), POSTGRES_PASSWORD: Joi.string().required(), POSTGRES_DB: Joi.string().required(), JWT_SECRET: Joi.string().required(), JWT_EXPIRATION_TIME: Joi.string().required(), PORT: Joi.number(), }) }), DatabaseModule, JwtModule.registerAsync({ imports: [ConfigModule], inject: [ConfigService], useFactory: async (configService: ConfigService) => ({ secret: configService.get('JWT_SECRET'), signOptions: { expiresIn: `${configService.get('JWT_EXPIRATION_TIME')}s`, }, }), }), ], providers: [ AuthenticationService ], }).compile(); authenticationService = await module.get<AuthenticationService>(AuthenticationService); }) describe('when creating a cookie', () => { it('should return a string', () => { const userId = 1; expect( typeof authenticationService.getCookieWithJwtToken(userId) ).toEqual('string') }) }) }); |
There are quite a few issues with the above code still. Let’s deal with them one by one.
Mocking the database connection
The biggest issue above is that we use the DatabaseModule which means connecting to the real database. When doing unit tests, we want to avoid it.
After removing the DatabaseModule from our imports we can see an error:
Error: Nest can’t resolve dependencies of the UserRepository (?). Please make sure that the argument Connection at index [0] is available in the TypeOrmModule context.
To work around it, we need to provide a mocked User repository. To do so, we need to use the getRepositoryToken from '@nestjs/typeorm.
1 |
import User from '../../users/user.entity'; |
1 2 3 4 5 6 7 |
providers: [ AuthenticationService, { provide: getRepositoryToken(User), useValue: {}, } ], |
Unfortunately, the above error persists. This is because we imported UsersModule that contains TypeOrmModule.forFeature([User]). We should avoid importing our modules when writing unit tests because we don’t want to test integration between classes just yet. We need to add UsersService to our providers instead.
src/authentication/tests/authentication.service.spec.ts
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import { AuthenticationService } from '../authentication.service'; import { Test } from '@nestjs/testing'; import { ConfigModule } from '@nestjs/config'; import { JwtModule } from '@nestjs/jwt'; import { getRepositoryToken } from '@nestjs/typeorm'; import User from '../../users/user.entity'; import { UsersService } from '../../users/users.service'; describe('The AuthenticationService', () => { let authenticationService: AuthenticationService; beforeEach(async () => { const module = await Test.createTestingModule({ imports: [ ConfigModule.forRoot({ // ... }), JwtModule.registerAsync({ // ... }), ], providers: [ UsersService, AuthenticationService, { provide: getRepositoryToken(User), useValue: {}, } ], }).compile(); authenticationService = await module.get<AuthenticationService>(AuthenticationService); }) describe('when creating a cookie', () => { it('should return a string', () => { const userId = 1; expect( typeof authenticationService.getCookieWithJwtToken(userId) ).toEqual('string') }) }) }); |
The object we put into useValue above is our mocked repository. We add some methods to it later below.
Mocking ConfigService and JwtService
Since we want to avoid using modules, we also can replace ConfigModule and JwtModule with mocks. To be more precise, we need to provide mocked ConfigService and JwtService.
A clean approach to that would be to create separate files for the above mocks.
src/utils/mocks/config.service.ts
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const mockedConfigService = { get(key: string) { switch (key) { case 'JWT_EXPIRATION_TIME': return '3600' } } } |
src/utils/mocks/jwt.service.ts
1 2 3 |
const mockedJwtService = { sign: () => '' } |
When we use the above, our test now looks like that:
src/utils/mocks/config.service.ts
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import { AuthenticationService } from '../authentication.service'; import { Test } from '@nestjs/testing'; import { ConfigService } from '@nestjs/config'; import { JwtService } from '@nestjs/jwt'; import { getRepositoryToken } from '@nestjs/typeorm'; import User from '../../users/user.entity'; import { UsersService } from '../../users/users.service'; import mockedJwtService from '../../utils/mocks/jwt.service'; import mockedConfigService from '../../utils/mocks/config.service'; describe('The AuthenticationService', () => { let authenticationService: AuthenticationService; beforeEach(async () => { const module = await Test.createTestingModule({ providers: [ UsersService, AuthenticationService, { provide: ConfigService, useValue: mockedConfigService }, { provide: JwtService, useValue: mockedJwtService }, { provide: getRepositoryToken(User), useValue: {} } ], }) .compile(); authenticationService = await module.get(AuthenticationService); }) describe('when creating a cookie', () => { it('should return a string', () => { const userId = 1; expect( typeof authenticationService.getCookieWithJwtToken(userId) ).toEqual('string') }) }) }); |
Changing the mock per test
We do not always want to mock something the same way in each test. To change our implementation between tests, we can use jest.Mock.
src/users/tests/users.service.spec.ts
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import { Test } from '@nestjs/testing'; import { getRepositoryToken } from '@nestjs/typeorm'; import User from '../../users/user.entity'; import { UsersService } from '../../users/users.service'; describe('The UsersService', () => { let usersService: UsersService; let findOne: jest.Mock; beforeEach(async () => { findOne = jest.fn(); const module = await Test.createTestingModule({ providers: [ UsersService, { provide: getRepositoryToken(User), useValue: { findOne } } ], }) .compile(); usersService = await module.get(UsersService); }) describe('when getting a user by email', () => { describe('and the user is matched', () => { let user: User; beforeEach(() => { user = new User(); findOne.mockReturnValue(Promise.resolve(user)); }) it('should return the user', async () => { const fetchedUser = await usersService.getByEmail('test@test.com'); expect(fetchedUser).toEqual(user); }) }) describe('and the user is not matched', () => { beforeEach(() => { findOne.mockReturnValue(undefined); }) it('should throw an error', async () => { await expect(usersService.getByEmail('test@test.com')).rejects.toThrow(); }) }) }) }); |
Summary
In this article, we’ve looked into how to write unit tests in NestJS. To do so, we’ve used the Jest library that comes bundled with NestJS. We’ve also used some of the built-in utilities to mock various services and modules properly. One of the most important ones was mocking the database connection so that we can keep our tests isolated.
amazing tutorials, thank you so much
thanks for the helpful contents
https://github.com/mwanago/nestjs-typescript/blob/master/src/users/tests/users.service.spec.ts
retuns error do you have any suggestion
—–
Nest can’t resolve dependencies of the UsersService (UserRepository, ?, Connection, StripeService, LocalFilesService). Please make sure that the argument DatabaseFilesService at index [1] is available in the RootTestModule context.
Potential solutions:
– If DatabaseFilesService is a provider, is it part of the current RootTestModule?
– If DatabaseFilesService is exported from a separate @Module, is that module imported within RootTestModule?
@Module({
imports: [ /* the Module containing DatabaseFilesService */ ]
})
You need to create a mock service for ‘DatabaseFilesService’, ‘StripeService’ & ‘localFilesService’.
In your providers array, do this for all 3 services:
{
provide: DatabaseFilesService,
useClass: FakeDatabaseFilesService,
}
and create a class for each fake service and define all methods of it like:
export class FakeDatabaseFilesService {
public async find(): Promise<void> {}
}
this article use typeorm version ^0.2.24. and my version is ^0.3.14. when I create UserService Instance, I have a problem with argument Repository<User>(). this argument create error that expect 2-3 argment(targetEntity, EntityManager, options). How can i solve this??
new UsersService(
dataSource.getRepository(User),
dataSource.getRepository(Address),
), use your datasourse – typeOrm.comfig.ts
You should use Test.createTestingModule() instead of manually doing the dependency injection. Wanago used that in the very next section.