Nest can't resolve dependencies in the RootTestModule context when I use Bazel Test - jestjs

Question

I need to run my tests in the bezel. how can I solve this mysterious problem?
I have a nestjs project contains multiple apps and libs. When I run the test yarn jest --config ./jest.config.json libs/lib1, it works perfectly. However when I run with bezel bazel test //libs/lib1/... it gives me an error "Nest can't resolve dependencies ... Please make sure that the argument dependency at index ... is available in the RootTestModule context.".
REPO
https://github.com/smhmayboudi/bazel_jest_nestjs
I find out that the order of mapping at jest.config.json is important.
this one works well ( shows test + coverage ), but dependency problem
"moduleNameMapper": {
"#melo/lib1": "<rootDir>/libs/lib1/src",
"#melo/lib1/(.*)": "<rootDir>/libs/lib1/src/$1",
},
this one works ( show just pass message with out actual test result and coverage !? )
"moduleNameMapper": {
"#melo/lib1/(.*)": "<rootDir>/libs/lib1/src/$1",
"#melo/lib1": "<rootDir>/libs/lib1/src",
},
Jest Config
{
"coverageReporters": ["lcov", "text-summary"],
"moduleNameMapper": {
"#melo/libs1": "<rootDir>/libs/libs1/src",
"#melo/libs1/(.*)": "<rootDir>/libs/libs1/src/$1",
},
"modulePathIgnorePatterns": ["/bazel-out/", "/node_modules/"],
"preset": "ts-jest",
"testEnvironment": "node"
}
Bazel Config
ts_library(
name = "lib1_test_ts_library",
srcs = glob(["*spec.ts"]),
runtime = "nodejs",
deps = [
":lib1_ts_library",
"#npm//#nestjs/common",
"#npm//#nestjs/testing",
"#npm//#types/jest",
"#npm//rxjs",
"#npm//ts-jest",
],
)
jest_test(
name = "lib1_jest_test",
srcs = glob(["*spec.ts"]),
jest_config = "//:jest.config.json",
deps = [
":lib1_test_ts_library",
],
coverage = True,
)
Error Log
INFO: Invocation ID: 84f45d55-c6e4-4c2a-b05d-367d0f84baf7
INFO: Analyzed target //libs/lib1/src:lib1_jest_test (633 packages loaded, 19569 targets configured).
INFO: Found 1 test target...
WARNING: failed to create one or more convenience symlinks for prefix 'dist/':
cannot create symbolic link bazel-out -> /Users/WHOAMI/Developer/MY_PROJECT/bazel-out/execroot/melo/bazel-out: /Users/WHOAMI/Developer/MY_PROJECT/bazel-out (File exists)
FAIL: //libs/lib1/src:lib1_jest_test (see /Users/WHOAMI/Developer/MY_PROJECT/bazel-out/execroot/melo/bazel-out/darwin-fastbuild/testlogs/libs/lib1/src/lib1_jest_test/test.log)
INFO: From Testing //libs/lib1/src:lib1_jest_test:
==================== Test output for //libs/lib1/src:lib1_jest_test:
PASS libs/lib1/src/lib1.util.spec.ts (23.866 s)
PASS libs/lib1/src/lib1.interceptor.spec.ts (23.977 s)
FAIL libs/lib1/src/lib1.service.spec.ts (24.717 s)
● ApmService › should be defined
Nest can't resolve dependencies of the ApmService (?). Please make sure that the argument dependency at index [0] is available in the RootTestModule context.
Potential solutions:
- If dependency is a provider, is it part of the current RootTestModule?
- If dependency is exported from a separate #Module, is that module imported within RootTestModule?
#Module({
imports: [ /* the Module containing dependency */ ]
})
at Injector.resolveSingleParam (../../../../../../../../node_modules/#nestjs/core/injector/injector.js:134:19)
at resolveParam (../../../../../../../../node_modules/#nestjs/core/injector/injector.js:102:49)
at Array.map (<anonymous>)
at Injector.resolveConstructorParams (../../../../../../../../node_modules/#nestjs/core/injector/injector.js:117:58)
at Injector.loadInstance (../../../../../../../../node_modules/#nestjs/core/injector/injector.js:81:20)
at Injector.loadProvider (../../../../../../../../node_modules/#nestjs/core/injector/injector.js:38:20)
at ../../../../../../../../node_modules/#nestjs/core/injector/instance-loader.js:43:62
at Array.map (<anonymous>)
at InstanceLoader.createInstancesOfProviders (../../../../../../../../node_modules/#nestjs/core/injector/instance-loader.js:43:36)
at ../../../../../../../../node_modules/#nestjs/core/injector/instance-loader.js:28:24
● ApmService › should be defined
expect(received).toBeDefined()
Received: undefined
56 |
57 | it("should be defined", () => {
> 58 | expect(service).toBeDefined();
| ^
59 | });
60 |
61 | it("start should be called", () => {
at Object.<anonymous> (libs/lib1/src/lib1.service.spec.ts:58:21)
...
Test Suites: 2 failed, 2 passed, 4 total
Tests: 27 failed, 3 todo, 6 passed, 36 total
Snapshots: 0 total
Time: 26.102 s
Ran all test suites within paths "libs/lib1/src/lib1.decorator.spec.ts", "libs/lib1/src/lib1.interceptor.spec.ts", "libs/lib1/src/lib1.service.spec.ts", "libs/lib1/src/lib1.util.spec.ts".
================================================================================
Target //libs/lib1/src:lib1_jest_test up-to-date:
dist/bin/libs/lib1/src/lib1_jest_test.sh
dist/bin/libs/lib1/src/lib1_jest_test_loader.js
dist/bin/libs/lib1/src/lib1_jest_test_require_patch.js
INFO: Elapsed time: 83.878s, Critical Path: 59.53s
INFO: 4 processes: 4 local.
INFO: Build completed, 1 test FAILED, 12 total actions
//libs/lib1/src:lib1_jest_test FAILED in 28.2s
/Users/WHOAMI/Developer/MY_PROJECT/bazel-out/execroot/melo/bazel-out/darwin-fastbuild/testlogs/libs/lib1/src/lib1_jest_test/test.log
INFO: Build completed, 1 test FAILED, 12 total actions

Answer 1

Add providers to your RootTestModule. Nest doesn't automatically include the services in your test, depending on if you used the cli vs creating the files/folders directly.
const module: TestingModule = await Test.createTestingModule({
providers: [/** Services goes here **/],
controllers: [CustomersController],
}).compile();
Not working vs Working below
import { Test, TestingModule } from '#nestjs/testing';
import { CustomersController } from './customers.controller';
describe('CustomersController', () => {
let controller: CustomersController;
beforeEach(async () => {
const module: TestingModule = await Test.createTestingModule({
controllers: [CustomersController],
}).compile();
controller = module.get<CustomersController>(CustomersController);
});
it('should be defined', () => {
expect(controller).toBeDefined();
});
it('shoud return customer', async () => {
const tcase = await controller.d({});
expect(tcase).toHaveProperty('firstName');
})
});
Working (I had the exact error message with different filenames ofcourse)
import { Test, TestingModule } from '#nestjs/testing';
import { CustomersController } from './customers.controller';
import { CustomersService } from './customers.service';
describe('CustomersController', () => {
let controller: CustomersController;
beforeEach(async () => {
const module: TestingModule = await Test.createTestingModule({
providers: [CustomersService],
controllers: [CustomersController],
}).compile();
controller = module.get<CustomersController>(CustomersController);
});
it('should be defined', () => {
expect(controller).toBeDefined();
});
it('shoud return customer', async () => {
const tcase = await controller.d({});
expect(tcase).toHaveProperty('firstName');
})
});

Answer 2

A potential workaround is to declare "empty"
beforeEach(async () => {
const module: TestingModule = await Test.createTestingModule({
providers: [{
provide: CustomerService,
useValue: {},
}],
controllers: [CustomersController],
}).compile();

Answer 3

The solution that worked for me was following the unit test examples of the library.
import { Test, TestingModule } from '#nestjs/testing';
import { CreateUserDto } from './dto/create-user.dto';
import { UsersController } from './users.controller';
import { UsersService } from './users.service';
const createUserDto: CreateUserDto = {
firstName: 'firstName #1',
lastName: 'lastName #1',
};
describe('UsersController', () => {
let usersController: UsersController;
let usersService: UsersService;
beforeEach(async () => {
const app: TestingModule = await Test.createTestingModule({
controllers: [UsersController],
providers: [ // <---------- THIS IS THE MOST IMPORTANT SECTION TO SOLVE THIS ISSUE.
{
provide: UsersService,
useValue: {
create: jest
.fn()
.mockImplementation((user: CreateUserDto) =>
Promise.resolve({ id: '1', ...user }),
),
findAll: jest.fn().mockResolvedValue([
{
firstName: 'firstName #1',
lastName: 'lastName #1',
},
{
firstName: 'firstName #2',
lastName: 'lastName #2',
},
]),
findOne: jest.fn().mockImplementation((id: string) =>
Promise.resolve({
firstName: 'firstName #1',
lastName: 'lastName #1',
id,
}),
),
remove: jest.fn(),
},
},
],
}).compile();
usersController = app.get<UsersController>(UsersController);
usersService = app.get<UsersService>(UsersService);
});
it('should be defined', () => {
expect(usersController).toBeDefined();
});
describe('create()', () => {
it('should create a user', () => {
expect(usersController.create(createUserDto)).resolves.toEqual({
id: '1',
...createUserDto,
});
expect(usersService.create).toHaveBeenCalled();
expect(usersService.create).toHaveBeenCalledWith(createUserDto);
});
});
describe('findAll()', () => {
it('should find all users ', () => {
usersController.findAll();
expect(usersService.findAll).toHaveBeenCalled();
});
});
describe('findOne()', () => {
it('should find a user', () => {
usersController.findOne('1');
expect(usersService.findOne).toHaveBeenCalled();
expect(usersController.findOne('1')).resolves.toEqual({
firstName: 'firstName #1',
lastName: 'lastName #1',
id: '1',
});
});
});
describe('remove()', () => {
it('should remove the user', () => {
usersController.remove('2');
expect(usersService.remove).toHaveBeenCalled();
});
});
});
The key change was to update the 'providers' property to use an object instead of just using: providers: [CustomersService],.