💡 code quality

🪕

📑 Code Quality Fundamentals

• comment conventions
• whitespace conventions
• naming
• error controls
• Linters
• Unit, integration, and functional testing

📑 TDD (test-driven development) vs BDD (behavior)

• TDD describes when, while BDD describes how and why.
• teardown (after) 拆除
• DSL: domain-specific language. An example of a DSL for testing framework interfaces is BDD

• Assertions library (node.js built-in)

  typeOf = Object.prototype.toString
  instanceOf = instance of constructor

• Assetion Library Examples | Assertion Library | Notes | | ----------------- | --------------------------- | | Assert | native, included in Node.js | | Chai | chaijs.com | | should.js | shouldjs.github.io | | code | github.com/hapijs/code |

📑 EditorConfig

• used by: Node.js, React, webpack
• Named .editorconfig
• INI format ?
• All properties and values are case insensitive

📑 Linters, ESLint

• syntax checkeers and validators
• node.js: built-in to node CLI: node —check script.js
• 3 linters: JSLint, JSHint, ESLint
• ESLint, extensible with plugins, most popular, most flexible, docs

• EsLint Shareable Configs:

  shareable configs	Notes
  eslint-config-airbnb	React style Guide, default
  eslint-config-standard	JS standard Style
  eslint-config-google	Google Style

• .eslintignore: ESLint can skip files and directories listed by globs.
• multiple .eslintrc.json files in sub-dirs to overwrite: ESLint configurations can inherit from a parent and override locally with a inherit.
• VSCode eslint plugins

📑 Unit Testing

• framework: AVA, Jasmine, Jest(React support), Mocha, tape
• library: Assert, Chai, code, should.js
• Chai: BDD and TDD assertion library
• Mocha + Chai
• should not use a done callback when testing a Promise
• chai-as-promised as optional with >Mocha 3
• context() is just an alias for describe(), and behaves the same way
• mocha default test folder is test/
• The BDD interface provides describe(), context(), it(), specify(), before(), after(), beforeEach(), and afterEach().
• The TDD interface provides suite(), test(), suiteSetup(), suiteTeardown(), setup(), and teardown().

📑 Test Doubles (测试替代): Stubs (存根), Spies, Mocks

• sinon.js: Sinon 通过所谓的测试替代(test-double) 轻松消除测试的复杂度。测试替代，顾名思义，测试中用到的是真实代码逻辑的替代品。
• sinon-chai: extends Chai with Sinon.js TDD assertions, not required to use sinon.js
• spies: 主要用途是收集有关函数调用的信息。一个 spies 可以告诉我们调用一个函数的次数、每次调用的参数、返回的值、抛出的错误等。
• stubs: 拥有 spies 的所有功能，不是监视某个函数的调用情况，而是完全取代了这个函数。换句话说，当使用 spies 时，原始函数仍然运行，但是当使用 stub 时，函数将不具有原始的功能，而是替换后的函数。
• mocks: 一个对象中的多个方法.

📑 Override dependencies with Proxyquire

• Proxyquire: prevent calls to original dependency, simulates module absences, cache behavior lik reload. Use proxyquire on app.js
• Mockery: replace dependency modules
• Revire: Overrides and inspects variables

📑 Code Coverage istanbul

• watch codes execution
• track how well unit tests exeercise codebase
• CLI interface is nyc
• support mocha, AVA, and others
• The four most typical types of code coverage are statements, branches, functions and lines.
• the nyc tool can generate coverage reports in formats including text, html and LCOV.

📑 Function testing Tools

• PhantomJS
• Selenium WebDriver

• SuperAgent: chai-http: uses a callback to provide an error and response.

  if('should rest work', (done) => {
    chai.request(app)
      .post('/rest')
      .set('content-type','application/x-www-form-urlencoded')
      .send({body: JSON.stringify(body)})
      .end(err => done(err))
  })

🪕 Coverage with continous integration

• Jenkins
• Strider CD: written in Node.js
• continous integration as a Service: TravisCI

🪕 Summary

• Quality: ESLint, Prettier, Airbnb, EditorConfig
• Unit Testing: Mocha + Chai
• Test Doubles: Sinonjs
• Code coverage generated: Istanbul, nyc
• Coverage with continuous integration: Jenkins, TravisCI