How to mock a controller? - node.js

Question

How to mock this I don't know. Can someone help me on this ?
I want to write the test case for this controller. But I am new to this so where to start and how to write the test case I don't understand.
import { Route } from '../common/ExpressWrapper';
import {partnerDao} from '../factory/AppFactory';
import { keysToLowerCase } from '../util/TpsUtil';
import ErrorResponse from '../models/common/ErrorResponse'
const constants = require('../constants');
const logger = require('../logger/index.ts')('controller/PartnerController');
const GetPartnerByPKController: Route = (req, res) => {
logger.debug("Entering GetPartnerByPKController()");
let uuid = req.params.uuid;
console.time("TimeTaken:DBCall:");
console.log("Entering GetPartnerByPKController()"+uuid);
partnerDao.getPartnerByUuid(uuid).then(result => {
if (result != undefined) {
res.status(200).send(result);
} else {
logger.info("Partner for the uuid:" + uuid + " was not found");
res.status(404).send(new ErrorResponse("Partner not found", "404.1.100", constants.ERROR_LINK + "404.1.100", []));
}
}).catch(error => {
console.log("Error in accessing GetPartnerByPK API", JSON.stringify(error))
logger.error("Error in accessing GetPartnerByPK API", JSON.stringify(error));
res.status(500).send(new ErrorResponse("Internal Server Error", "500.1.103", constants.ERROR_LINK + "500.1.103", [JSON.stringify(error.message)]));
});
console.timeEnd("TimeTaken:DBCall:");
logger.debug("Leaving GetPartnerByPKController()");
}

Answer 1

Here is the unit test solution:
controller.ts:
import { partnerDao } from "./AppFactory";
import ErrorResponse from "./ErrorResponse";
type Route = any;
const constants = {
ERROR_LINK: "ERROR_LINK",
};
export const GetPartnerByPKController: Route = async (req, res) => {
console.debug("Entering GetPartnerByPKController()");
let uuid = req.params.uuid;
console.time("TimeTaken:DBCall:");
console.log("Entering GetPartnerByPKController()" + uuid);
await partnerDao
.getPartnerByUuid(uuid)
.then((result) => {
if (result != undefined) {
res.status(200).send(result);
} else {
console.info("Partner for the uuid:" + uuid + " was not found");
res
.status(404)
.send(new ErrorResponse("Partner not found", "404.1.100", constants.ERROR_LINK + "404.1.100", []));
}
})
.catch((error) => {
console.log("Error in accessing GetPartnerByPK API", JSON.stringify(error));
console.error("Error in accessing GetPartnerByPK API", JSON.stringify(error));
res
.status(500)
.send(
new ErrorResponse("Internal Server Error", "500.1.103", constants.ERROR_LINK + "500.1.103", [
JSON.stringify(error.message),
]),
);
});
console.timeEnd("TimeTaken:DBCall:");
console.debug("Leaving GetPartnerByPKController()");
};
AppFactory.ts:
export const partnerDao = {
async getPartnerByUuid(id) {
return "real data";
},
};
ErrorResponse.ts:
export default class ErrorResponse {
public desc = "";
public args: any;
public code: string = "";
public message: string = "";
constructor(message, code, desc, args) {
this.message = message;
this.desc = desc;
this.args = args;
this.code = code;
}
}
controller.test.ts:
import { GetPartnerByPKController } from "./controller";
import { partnerDao } from "./AppFactory";
import sinon from "sinon";
import { expect } from "chai";
import ErrorResponse from "./ErrorResponse";
describe("GetPartnerByPKController", () => {
afterEach(() => {
sinon.restore();
});
it("should get parter by uuid correctly", async () => {
const mResponse = "fake data";
const getPartnerByUuidStub = sinon.stub(partnerDao, "getPartnerByUuid").resolves(mResponse);
const mReq = { params: { uuid: "123" } };
const mRes = { status: sinon.stub().returnsThis(), send: sinon.stub() };
await GetPartnerByPKController(mReq, mRes);
sinon.assert.calledWith(mRes.status, 200);
sinon.assert.calledWith(mRes.status().send, mResponse);
sinon.assert.calledWith(getPartnerByUuidStub, "123");
});
it("should 404", async () => {
const mResponse = undefined;
const getPartnerByUuidStub = sinon.stub(partnerDao, "getPartnerByUuid").resolves(mResponse);
const mReq = { params: { uuid: "123" } };
const mRes = { status: sinon.stub().returnsThis(), send: sinon.stub() };
await GetPartnerByPKController(mReq, mRes);
sinon.assert.calledWith(mRes.status, 404);
sinon.assert.calledWith(
mRes.status().send,
new ErrorResponse("Partner not found", "404.1.100", "ERROR_LINK" + "404.1.100", []),
);
sinon.assert.calledWith(getPartnerByUuidStub, "123");
});
it("should 500", async () => {
const mError = new Error("unknown error");
const getPartnerByUuidStub = sinon.stub(partnerDao, "getPartnerByUuid").rejects(mError);
const mReq = { params: { uuid: "123" } };
const mRes = { status: sinon.stub().returnsThis(), send: sinon.stub() };
await GetPartnerByPKController(mReq, mRes);
sinon.assert.calledWith(mRes.status, 500);
sinon.assert.calledWith(
mRes.status().send,
new ErrorResponse("Internal Server Error", "500.1.103", "ERROR_LINK" + "500.1.103", [
JSON.stringify(mError.message),
]),
);
sinon.assert.calledWith(getPartnerByUuidStub, "123");
});
});
Unit test result with coverage report:
GetPartnerByPKController
Entering GetPartnerByPKController()
Entering GetPartnerByPKController()123
TimeTaken:DBCall:: 21.633ms
Leaving GetPartnerByPKController()
✓ should get parter by uuid correctly
Entering GetPartnerByPKController()
Entering GetPartnerByPKController()123
Partner for the uuid:123 was not found
TimeTaken:DBCall:: 0.532ms
Leaving GetPartnerByPKController()
✓ should 404
Entering GetPartnerByPKController()
Entering GetPartnerByPKController()123
Error in accessing GetPartnerByPK API {}
Error in accessing GetPartnerByPK API {}
TimeTaken:DBCall:: 35.619ms
Leaving GetPartnerByPKController()
✓ should 500 (38ms)
3 passing (124ms)
--------------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
--------------------|----------|----------|----------|----------|-------------------|
All files | 98.51 | 100 | 91.67 | 98.41 | |
AppFactory.ts | 50 | 100 | 0 | 50 | 3 |
ErrorResponse.ts | 100 | 100 | 100 | 100 | |
controller.test.ts | 100 | 100 | 100 | 100 | |
controller.ts | 100 | 100 | 100 | 100 | |
--------------------|----------|----------|----------|----------|-------------------|
Source code: https://github.com/mrdulin/mocha-chai-sinon-codelab/tree/master/src/stackoverflow/59319054