I currently have an express app that does a bunch of logic on a controller.
One of the steps is to insert a record to the DB ( It uses ObjectionJS models ).
let user = await this.User.query(trx).insert(userData);
In an attempt to mock out the model, I have done :
let mockUser = {
query: jest.fn(() => {
return mockUser;
}),
insert: jest.fn(() => {
return mockUser;
}),
toJSON: jest.fn()
};
With this, I wanted to do an assertion:
expect(mockUser.query().insert).toBeCalledWith({ some: 'data' });
It seems I have missed something. When I run the tests, the code would reach the mock function insert. But jest complaints
You could use mockFn.mockReturnThis() to return this context.
E.g.
index.js:
export async function main(User) {
const trx = 'the trx';
const userData = {};
let user = await User.query(trx).insert(userData);
return user.toJSON();
}
index.test.js:
import { main } from './';
describe('47953161', () => {
it('should pass', async () => {
let mockUser = {
query: jest.fn().mockReturnThis(),
insert: jest.fn().mockReturnThis(),
toJSON: jest.fn().mockResolvedValueOnce({ id: 1 }),
};
const actual = await main(mockUser);
expect(actual).toEqual({ id: 1 });
expect(mockUser.query).toBeCalledWith('the trx');
expect(mockUser.query().insert).toBeCalledWith({});
expect(mockUser.query().insert().toJSON).toBeCalledTimes(1);
});
});
unit test result with coverage report:
PASS src/stackoverflow/47953161/index.test.ts (10.41s)
47953161
✓ should pass (7ms)
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.ts | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 12.783s, estimated 13s
source code: https://github.com/mrdulin/jest-codelab/tree/master/src/stackoverflow/47953161
Related
I'm trying to mock nanoid for my testing but it doesn't seem to be working.
my function
public async createApp(appDto: ApplicationDto): Promise<string> {
const appWithToken = { ...appDto, accessToken: nanoid() };
const application = await this.applicationModel.create(appWithToken);
return application.id;
}
My test:
beforeEach(() => {
mockRepository.create.mockResolvedValueOnce({ id: mockId });
});
test("creates application and returns an id", async () => {
const mockAppDto: ApplicationDto = { email: "123#mock.com" };
const application = await applicationService.createApplication(mockAppDto);
expect(mockRepository.create).toHaveBeenCalledWith(mockAppDto); //how do I mock the nanoid here?
expect(application).toBe(mockId);
});
So basically I'm struggling to figure out how to mock the nanoid which is generated inside the function.
I've tried the following at the top of the file:
jest.mock('nanoid', () => 'mock id');
however it doesn't work at all.
Any help would be appreciated!
You didn't mock the nanoid module correctly. It uses named exports to export the nanoid function.
Use jest.mock(moduleName, factory, options) is correct, the factory argument is optional. It will create a mocked nanoid function.
Besides, you can use the mocked function from ts-jest/utils to handle the TS type.
E.g.
Example.ts:
import { nanoid } from 'nanoid';
export interface ApplicationDto {}
export class Example {
constructor(private applicationModel) {}
public async createApp(appDto: ApplicationDto): Promise<string> {
const appWithToken = { ...appDto, accessToken: nanoid() };
const application = await this.applicationModel.create(appWithToken);
return application.id;
}
}
Example.test.ts:
import { nanoid } from 'nanoid';
import { Example, ApplicationDto } from './Example';
import { mocked } from 'ts-jest/utils';
jest.mock('nanoid');
const mnanoid = mocked(nanoid);
describe('67898249', () => {
afterAll(() => {
jest.resetAllMocks();
});
it('should pass', async () => {
mnanoid.mockReturnValueOnce('mock id');
const mockAppDto: ApplicationDto = { email: '123#mock.com' };
const mockApplicationModel = { create: jest.fn().mockReturnValueOnce({ id: 1 }) };
const example = new Example(mockApplicationModel);
const actual = await example.createApp(mockAppDto);
expect(actual).toEqual(1);
expect(mockApplicationModel.create).toBeCalledWith({ email: '123#mock.com', accessToken: 'mock id' });
});
});
test result:
PASS examples/67898249/Example.test.ts (9.134 s)
67898249
✓ should pass (4 ms)
------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
Example.ts | 100 | 100 | 100 | 100 |
------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 10.1 s
There is a ValidationError (custom made) being thrown on my invert function if no string is provided:
const invert = (str) => {
if (str === '') throw new ValidationError('String must no be empty.');
return str;
};
This line of code is not getting full coverage by my assertion while using Jest:
expect(() => invert('')).toThrow(ValidationError);
Is there a way to get coverage for this line?
You should have two test cases at least. One test throws an error, and one test is normal. E.g.
index.ts:
export class ValidationError extends Error {
constructor(message) {
super(message);
}
}
export const invert = (str) => {
if (str === '') throw new ValidationError('String must no be empty.');
return str;
};
index.test.ts:
import { invert, ValidationError } from './';
describe('64271662', () => {
it('should throw validation error if string is empty', () => {
expect(() => invert('')).toThrow(ValidationError);
});
it('should return string', () => {
expect(invert('teresa teng')).toBe('teresa teng');
});
});
unit test result with 100% coverage:
PASS src/stackoverflow/64271662/index.test.ts (9.867s)
64271662
✓ should throw validation error if string is empty (4ms)
✓ should return string (1ms)
----------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.ts | 100 | 100 | 100 | 100 | |
----------|----------|----------|----------|----------|-------------------|
Test Suites: 1 passed, 1 total
Tests: 2 passed, 2 total
Snapshots: 0 total
Time: 11.042s
I am testing a node.js controller file using mocha and chai and i'm unable to mock out the response object in my test
TestController.ts
export class TestController {
static async getTest(req:any, res:any, next:object) {
console.log("Test");
//some code here
res.status(200).json(result.rows);
}
and this works perfectly fine when I call the API, returns the right response etc. But when I try to test this Controller, here is what I have for my test file
Test.ts
it('Get Test method', async function () {
let req = {params: {testid: 12345}};
let res:any = {
status: function() { }
};
res.json = '';
let result = await TestController.getTest(req, res, Object);
});
I am not sure how to represent the response object here. If I just declare the variable res in the following way
let res:any;
I see the following error in my test
TypeError: Cannot read property 'json' of undefined
I am not sure how my response data structure res should be for making this test work.
You should use sinon.stub().returnsThis() to mock the this context, it allows you to call chain methods.
E.g.
controller.ts:
export class TestController {
static async getTest(req: any, res: any, next: object) {
console.log('Test');
const result = { rows: [] };
res.status(200).json(result.rows);
}
}
controller.test.ts:
import { TestController } from './controller';
import sinon from 'sinon';
describe('61645232', () => {
it('should pass', async () => {
const req = { params: { testid: 12345 } };
const res = {
status: sinon.stub().returnsThis(),
json: sinon.stub(),
};
const next = sinon.stub();
await TestController.getTest(req, res, next);
sinon.assert.calledWithExactly(res.status, 200);
sinon.assert.calledWithExactly(res.json, []);
});
});
unit test results with 100% coverage:
61645232
Test
✓ should pass
1 passing (14ms)
---------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
---------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
controller.ts | 100 | 100 | 100 | 100 |
---------------|---------|----------|---------|---------|-------------------
I am a bit new to testing and I have been stuck on this issue for quite some time. So I am trying to test a s3.upload() function to see if it called, not to see if it actually uploads the object. The only constraint is that I cannot use any npm packages to mock out the functionality of the s3 bucket.
I was trying to follow this tutorial (How to mock a function inside another function (which I am testing) using sinon?) that uses sinon as a stub, but instead use jest instead. Any help or guidance with issue is appreciated.
// function.js
const uploadToS3 = (params) => {
const response = s3.upload(params).promise();
return response;
}
// functions.test.js
describe("Lambda Handler Function", () => {
test('To test to see if the uploadToS3 function was called', () => {
const sampleParam = {
Bucket: 'BucketName',
Key: 'BucketKey.zip',
Body: 'SGVsbG8sIFdvcmxk'
}
expect(uploadToS3(sampleParam).response).toBeCalled()
})
})
You can use jest.mock(moduleName, factory, options) to mock aws-sdk.
E.g.
function.js:
import AWS from 'aws-sdk';
const s3 = new AWS.S3();
const uploadToS3 = async (params) => {
const response = await s3.upload(params).promise();
return response;
};
export { uploadToS3 };
function.test.js:
import { uploadToS3 } from './function';
import AWSMock from 'aws-sdk';
jest.mock('aws-sdk', () => {
const mS3 = { upload: jest.fn().mockReturnThis(), promise: jest.fn() };
return { S3: jest.fn(() => mS3) };
});
describe('60970919', () => {
it('should pass', async () => {
const mS3 = new AWSMock.S3();
const mResponse = { Bucket: 'xxx' };
mS3.upload({}).promise.mockResolvedValueOnce(mResponse);
const actual = await uploadToS3({});
expect(actual).toEqual(mResponse);
expect(mS3.upload).toBeCalledWith({});
expect(mS3.upload().promise).toBeCalled();
});
});
unit test results with 100% coverage:
PASS stackoverflow/60970919/function.test.js (13.818s)
60970919
✓ should pass (9ms)
-------------|---------|----------|---------|---------|-------------------
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
-------------|---------|----------|---------|---------|-------------------
All files | 100 | 100 | 100 | 100 |
function.js | 100 | 100 | 100 | 100 |
-------------|---------|----------|---------|---------|-------------------
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 15.486s
source code: https://github.com/mrdulin/react-apollo-graphql-starter-kit/tree/master/stackoverflow/60970919
I have an express app with a router I would like to test with Sinon. I'm not successful in mocking the response parameter that is passed into the request handler and would like some help.
export const pingHandler = (request, response, next) => {
response.status(200).send('Hello world');
}
This is my current test setup using Mocha, Sinon, Chai & sinon-chai. fakeRes.status was never called as expected.
describe("pingHandler", () => {
it("should return 200", async () => {
const fakeResponse = {
status: sinon.fake(() => ({
send: sinon.spy()
}))
};
pingHandler({}, fakeResponse, {});
expect(fakeResponse.status).to.have.been.called;
// => expected fake to have been called at least once, but it was never called
});
});
Here is the unit test solution:
index.ts:
export const pingHandler = (request, response, next) => {
response.status(200).send('Hello world');
}
index.spec.ts:
import { pingHandler } from "./";
import sinon from "sinon";
describe("pingHandler", () => {
it("should return 200", () => {
const mRes = {
status: sinon.stub().returnsThis(),
send: sinon.stub(),
};
pingHandler({}, mRes, {});
sinon.assert.calledWith(mRes.status, 200);
sinon.assert.calledWith(mRes.send, "Hello world");
});
});
Unit test result with 100% coverage:
pingHandler
✓ should return 200
1 passing (8ms)
---------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
---------------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
index.spec.ts | 100 | 100 | 100 | 100 | |
index.ts | 100 | 100 | 100 | 100 | |
---------------|----------|----------|----------|----------|-------------------|