Testing Node.js

• have descriptive test names,

• bad: isAgeValid(), good: age is between 15 and 100

• you're going to be reading this a lot

Tests -> Tools -> Patterns -> Design -> Tests -> ...

Mocha

• To test a feature, each describe should have a before which creates the scenario.

• each it specified the behaviour

• don't use arrow functions

• if you want to change mocha settings like this.timeout(2500)

• first describe block is the acceptance tests (integrity), should always be right will work if ...

• second describe block: should try to break things

• won't work if ...

• don't change things from another block

mocha tools

describe.only( ... )

• will only run that one describe

• also works for it.only(), USE THIS if that one test case fails

• it.skip() will skip that test case

• Print the results of the tests mocha --reporter doc > report.html

• can have nested directory sturcture, just have the npm test script in package.json:

scripts: {

test: "mocha ./test/**/*.spec.js"

}

Mocha and Asynchronous Code

// expects a callback

it('...', function(done) {

done(); // mocha will continue to run the next test

}

• can also use the mocha-generators module when dealing with promises

Sinon

• var func = sinon.spy()

• gives a fake function that can track lots of information

• can track how many times it was called, lots more

• for each, see what the args were

• watch an existing function

• sinon.stub(obj, 'function').returns(true): replace a function, control it to do what we want

• kills the function

• sinon.stub(obj, 'functionName').throws()

Sinon and event triggers

var spy = sinon.spy();

eventEmitter.on("validated", spy);

assert(spy.called);

obviously, this isn't fun, avoid using event triggers, use promises, or async

Sinon and database

sinon.stub(db, "find").yields(null, {id: 1});

Repository Design Pattern

• shouldn't use it over a large code base

Mocks

var mock = sinon.mock(res);

mock.expects('render').twice().withExactArgs('index');

• Singletons are not friendly to mocking

exports.aPropertyName = {}; is the only line in the file

Mocking HTTP

Problem 1: Https is a built-in node.js module

Solution

beforeEach(function() {

// we only want to stub the request function of https

this.request = sinon.stub(https, 'request');

});

Nock module (HTTP mocking)

• mock API calls from code to an external API

• mocking can be destructive, can cause more problems than it's worth

• don't mock something you don't own

• otherwise, you're going to have to do some sleuthing and look at module code

Problem 2: https uses a stream, we need to mock a stream

var PassThrough = require('stream').PassThrough;

var response = new PassThrough();

response.write(JSON.stringify({some: "json"});

response.end();

NeDB

• like SQLite for Node

• uses MongoDB syntax

Learning Paths

Fundamentals Track

• basic literacy, fundamental ideas (OOP, GPU, CPU, async)

• widely applicable

• rarely become obsolete

• can still be complex, not necessarily beginner

• can transfer to others

Information

• specific knowledge

• Fundamental: what is an int, Information: in C++

• obsolete very quickly

Skills

• use knowledge to get things done

• gets you income

Competence

• when you have lots of all three

• good enough

Innovation (expertise)

• After competence

• tracks after the first three

• creates the fundamentals, information, skills

• hard work, usually by accident, they're passionate about a technology and end up an expert

Choosing a platform over a language

• OS platforms (Android)

• Application Platforms (Facebook, Drupal)

• API Platforms (Twitter, Amazon, Google)

• Delivery platforms (AWS, Azure, Heroku)

Where do you start?

• books, courses, have curation

Certificates

• valuable if employees want them

• open source contributions

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Last update: 2023-04-24