Nestjs Jest Unit Test: Basic test failure - Jest configuration - jestjs

Question

I have a simple Jest test for my Nest JS project.
The Jest looks like:
import { Test, TestingModule } from '#nestjs/testing';
import { IbmVpcController } from './ibm.vpc.controller';
import { IbmVpcServiceMock } from './ibm.vpc.service.mock';
import { ModuleMocker, MockFunctionMetadata } from 'jest-mock';
import { MOCKED_VPC } from '../../repository/ibm/mock.vpc.data';
const moduleMocker = new ModuleMocker(global);
describe('IbmVpcController', () => {
let controller: IbmVpcController;
beforeEach(async () => {
const module: TestingModule = await Test.createTestingModule({
controllers: [IbmVpcController],
providers: [IbmVpcServiceMock]
})
.useMocker((token) => {
if (token === IbmVpcServiceMock) {
return {
list: jest.fn().mockResolvedValue(MOCKED_VPC.VPCs),
get: jest.fn().mockResolvedValue(MOCKED_VPC.VPCs[0]),
create: jest.fn().mockResolvedValue(MOCKED_VPC.VPCs[0]),
update: jest.fn().mockResolvedValue(MOCKED_VPC.VPCs[0]),
};
}
if (typeof token === 'function') {
const mockMetadata = moduleMocker.getMetadata(token) as MockFunctionMetadata<any, any>;
const Mock = moduleMocker.generateFromMetadata(mockMetadata);
return new Mock();
}
})
.compile();
controller = module.get<IbmVpcController>(IbmVpcController);
});
it('should be defined', () => {
expect(controller).toBeDefined();
});
});
My jest.config.js looks like:
module.exports = {
verbose: true,
preset: "ts-jest",
testEnvironment: "node",
roots: ["./src"],
transform: { "\\.ts$": ["ts-jest"] },
testRegex: "(/__test__/.*|(\\.|/)(spec))\\.ts?$",
moduleFileExtensions: ["ts", "tsx", "js", "jsx", "json", "node"],
transformIgnorePatterns: [
'<rootDir>/node_modules/',
],
globals: {
"ts-jest": {
tsconfig: {
// allow js in typescript
allowJs: true,
},
},
},
};
However it is failing with the following error:
FAIL apps/protocols/src/ibm/vpc/ibm.vpc.controller.spec.ts
● Test suite failed to run
Jest encountered an unexpected token
This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.
By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/en/ecmascript-modules for how to enable it.
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/en/configuration.html
Details:
C:\Users\pradipm\clients\CloudManager\cm_6\occm\client-infra\nest-services\node_modules\axios\index.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import axios from './lib/axios.js';
^^^^^^
SyntaxError: Cannot use import statement outside a module
at Runtime.createScriptFromCode (../../node_modules/jest-runtime/build/index.js:1350:14)
at Object.<anonymous> (../../node_modules/retry-axios/src/index.ts:124:1)
Now able to get it what I am missing in my typescript Nest's Jest configuration.
Basically I tried out some more options also:
I tried out specifying the transformIgnorePatterns as only '/node_modules/'.
Tried out excluding the lodash-es', 'axios'
Tried out transformIgnorePattens as '/lib/' (where axois is there)
Added allowJs: true in the tsconfig.app.json compileOptions.
Any help to get trough my first basic test would be helpful.

Answer 1

With axios version 1.1.2 there's a bug with jest. You can resolve it by adding moduleNameMapper: { '^axios$': require.resovle('axios') } to your jest configuration