Set Mock Response for JWT Module NodeJS - node.js

Question

I am writing Test case using JEST in NodeJs inside AzureFunction.
Im trying to mock JWT module outcome inside my index.test.js , however its not working and getting timedout. I wonder is it the return datatype mismatch? How to set response similar to cb of jwt verify method?
Here is my sample code. Please suggest!
Index.js
const JWT = require('./jwtDecoder')
module.exports = function(context, req) {
try {
JWT(req.body, process.env.jwtsecret, function(err, decoded) {
if (err) {
context.log("Invalid JWT::" + req.body);
context.res = {
headers: {
'Content-Type': 'application/json'
},
status: 400,
body: {
"error": err
}
};
context.done();
} else {
context.log("JWT Authentication Successful:");
context.res = {
headers: {
'Content-Type': 'application/json'
},
status: 200,
body: {
"message": "success"
}
};
context.done();
}
});
} catch (err) {
context.log("Exception in main function, PushHttpFunction:" + err);
context.res = {
headers: {
'Content-Type': 'application/json'
},
status: 500,
body: {
"error": err
}
};
context.done();
}
}
jwtDecoder.js
'use strict';
module.exports = (body, secret, cb) => {
console.log('inside jwtDecoder');
if (!body) {
return cb(new Error('invalid jwt data'));
}
require('jsonwebtoken').verify(body.toString('utf8'), secret, { algorithm: 'HS256' }, cb);
};
index.test.js
let indexTest = require('../index')
const { runStubFunctionFromBindings } = require('stub-azure-function-context')
let JWT = require('../jwtDecoder')
jest.mock("../jwtDecoder.js")
/* verify.mockImplementation(() => () => ({
err: new Error('invalid jwt data'),
decoded: 'ok'
})); */
JWT.mockImplementation(() => new Promise(function(resolve, reject) {
resolve('ok');
}));
beforeAll(() => {
process.env = Object.assign(process.env, {
NODE_ENV: "test",
});
});
describe('Simple Testing', () => {
test('return 200 by mocking simpleFunc response" ', async() => {
let request = {
body: "dummy.jwt.zT5p"
};
const context = await runStubFunctionFromBindings(indexTest, [
{ type: 'httpTrigger', name: 'req', direction: 'in', data: request },
{ type: 'http', name: 'res', direction: 'out' },
], new Date());
console.log('mockedResp::', context);
expect(context.res.status).toEqual(200);
}, 30000);
});

Answer 1

Basically you are mocking wrong, you can keep only this line:
jest.mock('./jwtDecoder.js', () => (res, req, cb) => cb(null, 'ok'))
as you need to mock callback
and remove all this part:
jest.mock("../jwtDecoder.js")
JWT.mockImplementation(() => new Promise(function(resolve, reject) {
resolve('ok');
}));