Testing and validating Web Applications

Sylvain Fargier (BE-CEM-MRO)

01/06/21

Introduction

  • This presentation aims to:
    • Present a set of tools and methodology
    • Open discussion on test-driven-development for web-applications
  • It is not:
    • A recommendation or guideline document
    • A document to debate on technologies

Introduction: forewords

Introduction: General Overview

  • Web-Application
    • Dynamic web-page that interacts with a middle-ware
    • Similar to a regular application
  • Web-Site
    • Static web-page
    • May interact with a middleware (ex: database)
    • Does not display "live" values

Introduction: Web-Application

Back-end tests

  • Mocha.js test framework
    • BDD/TDD oriented : beforeEach(), afterEach(), describe() and it()
  • Basic, yet full of features
    • async/await, timeout, retry
    • code-coverage (nyc), Junit, browser-support ...

Back-end tests: framework

BDD like console output

describe('KnexREST tests', function() {

  it('can list databases', async function() {
    /* ... */
  });
});

source: mrest.js (BE-CEM-MRO)

  • Chai.js assertion library
    • BDD/TDD oriented : expect, assert, should
    • `expect` syntax eases the code lecture

Back-end tests: assertions

diff error details

/*...*/  
expect(ret).to.deep.include({ status: 200, body: [
  { id: 1, name: 'toto', value: 42 },
  { id: 2, name: 'titi', value: 43 },
  { id: 3, name: 'titi', value: 43 }
] });

source: mrest.js (BE-CEM-MRO)

  • Sinon.js spying, mocking and stubbing library
    • Can replace, spy or mock anything
    • Using sandbox to easily cleanup

Back-end tests: mocks & stubs

sinon.spy(DnsClient.prototype, 'query');
return q()
.then(() => DicRpc.invoke(/*...*/))
.then(
  () => { throw 'should fail'; },
  (err) => {
    expect(err).to.be.instanceOf(NotFound);
    
    expect(DnsClient.prototype.query.callCount)
    .to.equal(1, 'should query the DNS only once');
  })
.finally(() => DnsClient.prototype.query.restore());

ex: checks that a deeply nested object is used only once, source: dim.js  (BE-CEM-MRO)

  • Sinon.js is heavily artilery
    • Used really seldomly
  • Hand-written stubs are more effective
    • Use SQlite when a DB is needed, ex: mrest.js
    • Implement both server and client part, ex: dim.js, cmw-core.js
    • Stub complete devices/middleware, ex: ntof-stubs
    • Those piece of codes are intensively re-used (for both back-end and front-end tests) !

Back-end tests: mocks & stubs

 

  • GitLab-CI integration:
    • Test results and reports are processed by GitLab
    • Using an helper library (BE-CEM-MRO) to simplify the setup
    • Still exposing complete reports

Back-end tests: static analysis

source: coverage report

Front-end tests

  • Browser code (ECMAScript, CSS, HTML)
    • A library: only front-end code
    • Or an application: Node.js back-end + front-end
  • Bundled using WebPack
  • Transpiled with Babel
  • Running in "moving" environment
    • Must be tested ! tested again ! and again !

Front-end tests: Introduction

  • All back-end tools are re-used
    • Mocha.js test framework
    • Chai.js assertion library
    • Sinon.js spy and mocks library
    • Eslint, Jshint, JSDoc/TypeScript ...
  • Some additional tools are needed to:
    • Run the code in browsers
    • Interact with DOM (as a regular user would do)

Front-end tests: Introduction

  • Karma test runner
    • Supports main browsers (Chrome, Firefox, Safari ...)
    • Headless mode
    • Integrates with WebPack, Mocha, nyc ...

Front-end tests: test runner

asciinema record : base-vue (BE-CEM-MRO) tests in Headless Firefox (speed x2.5)

  • Karma debugging
    • Watch mode for TDD/BDD (fasten bundling)
    • Real  browser connection (console, analysis ...)

Front-end tests: test runner

mocha report with user control over tests

Chrome running ssvg-engine (BE-CEM-MRO) test suite

  • Karma.js integration
    • Using an helper library (BE-CEM-MRO)
    • In GitLab-CI using helper scripts (BE-CEM-MRO)
    • For Web-Applications, front-end and back-end test results are merged (code-coverage, results, static-analysis ...)

Front-end tests: test runner

const
  { karmaConfig } = require('karma-mocha-webpack');

module.exports = function(karma) {
  karma.set(karmaConfig(karma));
};

base-vue (BE-CEM-MRO) configuration using karma-mocha-webpack (BE-CEM-MRO)

  • Vue-test-utils unit testing utility library
    • Utilities to manipulate DOM and trigger events
  • Some home made utilities
    • to wait for application states (ex: wait for animation to settle, or asynchronous work to finish)

Front-end tests: user interactions

it('can use a dialog', async function() {
  wrapper = mount(BaseDialog, { propsData: { title: 'test dialog' } });

  let prom = wrapper.vm.request();
  let button = await waitForWrapper(wrapper,
    () => wrapper.findAll('button').filter((b) => b.text() === 'Ok'));
  button.trigger('click');
  expect(await prom).to.equal(true);
  /*...*/
});

base-vue (BE-CEM-MRO) Dialog testing

  • karma-server-side
    • Run code on the karma server side (Node.js)
    • Re-use stubs and back-end code we saw earlier (now it all makes sense 🎉)
    • Use Mocha beforeEach/afterEach to setup a custom middleware for each test

Front-end tests: middleware interactions

await server.run(function() {
  const { EACSStub } = serverRequire('ntof-stubs');
  this.env.stub.eacs.state.setState(EACSStub.EACSState.State.RUNNING);
});

n_ToF operation application (op-control)

  • So far we've focused on unit-tests
    • Represents about 80% of bugs (totally arbitrary number)
  • For the remaining bugs: continuous delivery
    • Deploy early, test often, give some attention to your work !
    • Be thankful to IT for the awesome infrastructure they provide !

Front-end tests: continuous integration

Front-end tests: continuous integration

BE-CEM-MRO deployment workflow for web-apps

Questions ?

Testing and validating Web Applications

By Sylvain fargier

Testing and validating Web Applications

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