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How to stub a dependency in express middleware (express-validator/mocha/chai/sinon/proxyquire)

**Edit: Re-written with a simple example that works first:
So I've got a test file and 2 modules.
moduleA has a dependency, moduleB
// moduleA.js
const ModuleB = require('./moduleB');
function functionA() {
return 20 + ModuleB.functionB();
};
module.exports = { functionA };
// moduleB.js
const functionB = () => {
return 10;
}
module.exports = { functionB }
My test file stubs out functionB (returned from moduleB) using proxyquire:
const sinon = require('sinon');
const proxyquire = require('proxyquire');
describe('Unit Tests', function() {
it('should work', () => {
const mockedFn = sinon.stub();
mockedFn.returns(30);
const copyModuleA = proxyquire('./moduleA', {
'./moduleB': {
functionB: mockedFn
}
});
console.log(copyModuleA.functionA());
})
});
So it outputs 50 (stubbed functionB 30 + functionA 20)
Now I'm trying to take this example into my code:
moduleA in this case is a file called validation.js. It is dependent on moduleB, in this case a sequelize model, Person, with the function I want to mock: findOne
validation.js exports module.exports = { validateLogin };, a function that calls validate, which returns a function that uses Person.findOne()
So in my mind, as with the simple example, I need to create a stub, point to the validation module in proxyquire, and reference the dependency and its findOne function. Like this:
const stubbedFindOne = sinon.stub();
stubbedFindOne.resolves();
validationModule = proxyquire('../../utils/validation', {
'../models/Person': {
findOne: stubbedFindOne
}
});
This should stub Person.findOne in validation.js. But it doesn't seem to. And I have no idea why.
let validationModule;
describe('Unit Tests', () => {
before(() => {
const stubbedFindOne = sinon.stub();
stubbedFindOne.resolves();
validationModule = proxyquire('../../utils/validation', {
'../models/Person': {
findOne: stubbedFindOne
}
});
})
it.only('should return 422 if custom email validation fails', async() => {
const wrongEmailReq = { body: {email: 'nik#hotmail.com'} };
const res = {
statusCode: 500,
status: (code) => {this.statusCode = code; return this},
};
const validationFn = validationModule.validateLogin();
const wrongEmail = await validationFn(wrongEmailReq, res, ()=>{});
expect(wrongEmail.errors[0].msg).to.be.equal('Custom Authorisation Error');
return;
})
And this is my validation.js file:
const Person = require('../models/Person');
// parallel processing
const validate = validations => {
return async (req, res, next) => {
await Promise.all(validations.map(validation => validation.run(req)));
const errors = validationResult(req);
if (errors.isEmpty()) {
return next();
}
const error = new Error();
error.message = process.env.NODE_ENV === 'development'? 'Validation Failed':'Error';
error.statusCode = !errors.isEmpty()? 422:500;
error.errors = errors.array({onlyFirstError: true});
next(error);
return error;
};
};
const validateLogin = () => {
const validations = [
body('email')
.isString()
// snip
.custom(async (value, {req}) => {
try{
const person = await Person.findOne({ where: { email: value } });
if(!person) return Promise.reject('Custom Authorisation Error');
} catch(err) {
throw err;
}
})
.trim(),
];
return validate(validations);
}
module.exports = {
validateLogin
};

So the code in both the small sample and my app is correct, apart from how I stub the function. It shouldn't resolve or reject anything (I tried both out of desperation). It should return null in order to satisfy the conditional rather than jump to the catch block:
try{
const person = await Person.findOne({ where: { email: value } });
if(!person) return Promise.reject('Custom Authorisation Error');
} catch(err) {
throw err;
}
Hope the simple example helps someone else with proxyquire though

module.exports with function

I have several JavaScript files that I create enums. for example:
source.enum.js
const enumUtils = require('../enum.utils');
const EmailAddressesSourceType = enumUtils.createEnum([
['DIRECTORY', 'directory'],
['FILE', 'file'],
['ARRAY', 'array']
]);
module.exports = { EmailAddressesSourceType };
The enum.utils.js is just a file that do the simple function of creating an enum from array:
class EnumUtils {
constructor() { }
// This method takes a map of elements and converts them to freeze objects (an enum-like object).
createEnum(mapItems) {
if (!mapItems || mapItems.length <= 0) {
throw new Error(`No array received: ${mapItems} (1000000)`);
}
const mapList = new Map([...mapItems]);
const symbolMap = {};
mapList.forEach((value, key) => { symbolMap[key] = value; });
return Object.freeze(symbolMap);
}
}
const enumUtils = new EnumUtils();
module.exports = enumUtils;
Now since I have 5-6 js files with enums, I want to avoid 'const enumUtils = require('../enum.utils');' in each of them, and do it all together in index.js file, something like this:
const { EmailAddressStatus, EmailAddressType, SendEmailStepName } = require('./files/emailAddress.enum');
const { Placeholder } = require('./files/placeholder.enum');
const { EmailAddressesSourceType } = require('./files/sources.enum');
const { Mode, Status, Method } = require('./files/system.enum');
const { StatusIcon, Color, ColorCode } = require('./files/text.enum');
const createEnum = (mapItems) => {
if (!mapItems || mapItems.length <= 0) {
throw new Error(`No array received: ${mapItems} (1000000)`);
}
const mapList = new Map([...mapItems]);
const symbolMap = {};
mapList.forEach((value, key) => { symbolMap[key] = value; });
return Object.freeze(symbolMap);
};
module.exports = {
createEnum(Color), createEnum(ColorCode), createEnum(EmailAddressStatus), createEnum(EmailAddressType), createEnum(EmailAddressesSourceType),
createEnum(Method), createEnum(Mode), createEnum(Placeholder), createEnum(SendEmailStepName), createEnum(Status), createEnum(StatusIcon)
};
But, there are compilation error in:
module.exports = {
createEnum(Color), createEnum(ColorCode), createEnum(EmailAddressStatus), createEnum(EmailAddressType), createEnum(EmailAddressesSourceType),
createEnum(Method), createEnum(Mode), createEnum(Placeholder), createEnum(SendEmailStepName), createEnum(Status), createEnum(StatusIcon)
};
My question is, there is a workaround so enable me to reduce the 'const enumUtils = require('../enum.utils');' in each file of the enums js file?
Thanks!
UPDATE 1
The error I'm getting is this:
The current status of the file (before I was trying to refactor) - It works OK:
index.js
const { EmailAddressStatus, EmailAddressType, SendEmailStepName } = require('./files/emailAddress.enum');
const { Placeholder } = require('./files/placeholder.enum');
const { EmailAddressesSourceType } = require('./files/sources.enum');
const { Mode, Status, Method } = require('./files/system.enum');
const { StatusIcon, Color, ColorCode } = require('./files/text.enum');
module.exports = {
Color, ColorCode, EmailAddressStatus, EmailAddressType, EmailAddressesSourceType,
Method, Mode, Placeholder, SendEmailStepName, Status, StatusIcon
};

This guy, guy-incognito, solved for me the issue. Now it works like a charm. Thanks man!
const { EmailAddressStatus, EmailAddressType, SendEmailStepName } = require('./files/emailAddress.enum');
const { Placeholder } = require('./files/placeholder.enum');
const { EmailAddressesSourceType } = require('./files/sources.enum');
const { Mode, Status, Method } = require('./files/system.enum');
const { StatusIcon, Color, ColorCode } = require('./files/text.enum');
const createEnum = (mapItems) => {
if (!mapItems || mapItems.length <= 0) {
throw new Error(`No array received: ${mapItems} (1000000)`);
}
const mapList = new Map([...mapItems]);
const symbolMap = {};
mapList.forEach((value, key) => { symbolMap[key] = value; });
return Object.freeze(symbolMap);
};
module.exports = {
Color: createEnum(Color),
ColorCode: createEnum(ColorCode),
EmailAddressStatus: createEnum(EmailAddressStatus),
EmailAddressType: createEnum(EmailAddressType),
EmailAddressesSourceType: createEnum(EmailAddressesSourceType),
Method: createEnum(Method),
Mode: createEnum(Mode),
Placeholder: createEnum(Placeholder),
SendEmailStepName: createEnum(SendEmailStepName),
Status: createEnum(Status),
StatusIcon: createEnum(StatusIcon)
};

JavaScript: Jest doesn't recognise static functions

I'm following a tutorial which is using jest to test the javascript. The instructor created a static function called genesis() on a class called Block and it worked for him just fine, but when I tried to do it I got TypeError: block.genesis is not a function. If I remove the static keyword it recognises the function and the test passes.
Here is the class:
const { GENESIS_DATA } = require('./config');
class Block {
constructor({ timestamp, lastHash, hash, data }) {
this.timestamp = timestamp;
this.lastHash = lastHash;
this.hash = hash;
this.data = data;
}
static genesis() {
return new Block(GENESIS_DATA);
}
}
module.exports = Block;
And the test:
const Block = require('./block');
const { GENESIS_DATA } = require('./config');
describe('Block', () => {
const timestamp = 'a-date';
const lastHash = 'a-hash';
const hash = 'another-hash';
const data = ['blockchain', 'data'];
const block = new Block({ timestamp, lastHash, hash, data });
describe('genesis()', () => {
const genesisBlock = block.genesis();
it('returns a block instance', () => {
expect(genesisBlock instanceof Block).toBe(true);
});
it('returns the genesis data', () => {
expect(genesisBlock).toEqual(GENESIS_DATA);
});
});
});

The genesis method is part of the class, not the instance. You want to call Block.genesis() instead of block.genesis()

How to test promises chain using jest?

I have module executer that will be executed on every api request now i am trying to write cases to unit test that executer. I have promise that returns chain that is being executed based on response. I see issue executing promise in test case , any help here to proper test this use case will be apprecaited.
main.ts
export class Executor {
private passedParam: ILogParams = {} as ILogParams;
constructor(public identity: Identity) {
this._ajv = new Ajv();
}
public execute(moduleName: string): (param1, param2) => any {
const self = this;
// getting rid of the tslint issue with Function
return function(params: any, responseCallback: (param: any , param2: any) => any) {
let _mod;
let _httpRequest;
let _params;
Promise.resolve(getApiModule(self.identity, moduleName))
.then((mod: ModuleBase<any, any>) => {
_mod = mod;
mod.ExecStage = ExecStage.Init;
return mod.init(getHttpModule(self.identity), params);
})
.then((httpRequest: HttpRequestBase) => {
_httpRequest = httpRequest;
if (_mod.Response().Summary.Header) {
throw _mod.Response().Summary;
}
return httpRequest;
})
.then(() => {
// empty the error stack
_mod.objErrorHandler.RemoveAllError();
_mod.ExecStage = ExecStage.Before;
return _mod.before(params);
})
.then((params1: any) => {
const _validators = _mod.getValidators();
let _failed: boolean = false;
return params1;
})
.then((params2: any) => {
_params = params2;
_mod.ExecStage = ExecStage.Core;
return _mod.core(_params, _httpRequest);
})
.catch((data: any) => {
const error: IHeader = {} as IHeader;
})
.then((data: any) => {
responseCallback(data, moduleName.substr(moduleName.indexOf('/') + 1));
});
};
}
}
main.spec.ts
import * as sinon from "sinon";
import {ModuleExecutor} from "./main.ts";
import {ExecStage, Identity} from "../../src/ts/common/Enums";
import ValidateRequestSchema from "../../src/ts/validation/requestSchema.js";
describe("ModuleExecuter", () => {
const sandbox = sinon.createSandbox();
afterEach(function afterTests() {
sandbox.restore();
});
let executer;
let executerSpy;
let results;
let stubbedExecutor;
let apiModule;
let _this;
const stubbedExecutorReturnFuction = sandbox.spy(function(args) {
executer = new ModuleExecutor(Identity.node);
executerSpy = executer.execute();
_this = this;
return new Promise(function(resolve) {
// moduleExecutor.execute(params, callback function)
executerSpy(args, function(data) {
resolve(data.Details);
});
});
});
const stubbedExecutorReturn = sandbox.spy(function(args, innerFunc) {
return innerFunc({Details: successResponse});
});
beforeEach(function() {
stubbedExecutor = sandbox.stub(ModuleExecutor.prototype, "execute").callsFake(function() {
return stubbedExecutorReturn;
});
apiModule = new GetAccountBalance();
const execute = sandbox.spy(stubbedExecutorReturnFuction);
results = execute("Payments/accountBalance/GetAccountBalance", {test:"test"});
});
describe("ModuleExecutor", function() {
it('should call ModuleExecutor.execute', function () {
sinon.assert.calledOnce(stubbedExecutor);
});
it('should return a promise', function() {
results.then(function(data) {
expect(data).toBe(successResponse);
});
});
it('should check validate AJV schema', function() {
let _mod;
results.then((mod: ModuleBase<any, any>) => {
_mod = mod;
mod.ExecStage = ExecStage.Before;
const requestSchema = "I" + _mod.__proto__.constructor.name + "Param";
const classSchema = ValidateRequestSchema[requestSchema];
const valid = _this._ajv.validate(classSchema, {test:"test"});
console.log("BOOLEAN>>>>>>>", valid);
expect(valid).toBeTruthy();
});
});
});
});

How to use createSpyObj properly

I am trying to test the getDatabase Version function will pass the query as in to the executeQuery function in the getQueryResult() called by getDatabase.
The code is as follows:
`
var RequestHandler = function () {
this.getQueryResult = function (sQuery) {
this.checkConnection();
try {
return this.conn.executeQuery.apply(this.conn, arguments);
} catch (err) {
this.conn.close();
this.conn = null;
throw "unexpected error, please check application trace files for more information";
}
};
this.getDatabaseVersion = function() {
var query = "select top 1 VERSION from M_DATABASE";
return this.getQueryResult(query)[0].VERSION;
};
}
`
The test case that I wrote:
`
var RHandler = $.import("sap.hana.graph.viewer.XS_Backend.js.lib", "RequestHandler").RequestHandler;
describe ("getDatabaseVersion Tests", function (){
var rHandler = null;
var getQueryResult = jasmine.createSpyObj('getQueryResult', ['conn', 'executeQuery', 'close']);
var conn = jasmine.createSpyObj('conn', ['executeQuery', 'close']);
beforeEach(function() {
rHandler = new RHandler();
rHandler.openConnection();
});
function getAllQueries() {
return getQueryResult.conn.executeQuery.calls.allArgs().join(':::');
}
it('should return the databaseVersion and match the query sent to getQueryResult', function() {
rHandler.getDatabaseVersion();
expect(rHandler.getDatabaseVersion()).toEqual("2.00.030.00.1502184660");
expect(getAllQueries()).toEqual(/select top 1 VERSION from M_DATABASE/i);
});
});
`
But it doesn't work at all. I am approaching in a wrong way. Can anyone guide me or let me know what I am doing wrong.

You need something like that:
var RHandler = $.import("sap.hana.graph.viewer.XS_Backend.js.lib", "RequestHandler").RequestHandler;
describe('RequestHandler', () => {
let rHandler = null;
let connection = null
beforeEach(() => {
connection = jasmine.createSpyObj('conn', ['executeQuery', 'close'])
rHandler = new RHandler();
rHandler.conn = connection;
});
describe('getQueryResult', () => {
beforeEach(() => {
spyOn(rHandler, 'checkConnection');
});
it('should check connection', () => {
rHandler.getQueryResult();
expect(rHandler.checkConnection).toHaveBeenCalled();
});
it('should execute query', () => {
connection.executeQuery.and.returnValue('foo');
const actual = rHandler.getQueryResult('bar', 'baz');
// toHaveBeenCalledWithContext
// https://www.npmjs.com/package/jasmine-spy-matchers
expect(connection.executeQuery).toHaveBeenCalledWithContext(connection, 'bar', 'baz');
// or default toHaveBeenCalledWith
expect(connection.executeQuery).toHaveBeenCalledWith('bar', 'baz');
expect(actual).toBe('foo');
});
it('should throw error', () => {
connection.executeQuery.and.throwError(new Error('some error message'));
expect(() => {
rHandler.getQueryResult('bar', 'baz');
}).toThrow('unexpected error, please check application trace files for more information');
expect(rHandler.conn).toBe(null);
});
});
describe('getDatabaseVersion', () => {
it('should return version', () => {
spyOn(rHandler, 'getQueryResult').and.returnValue([{VERSION: '2.00.030.00.1502184660'}])
const actual = rHandler.getDatabaseVersion();
expect(rHandler.getQueryResult).toHaveBeenCalledWith('select top 1 VERSION from M_DATABASE')
expect(actual).toBe('2.00.030.00.1502184660');
});
});
});