@knowark/injectarkjs/lib/builder.test.js

Dependency Injector for Javascript

import { describe, it, expect } from '@jest/globals'
import { Builder } from './builder.js'
import { Factory } from './factory.js'

describe('Builder', function () {
  let builder = null

  class AlphaFactory extends Factory {
    alphaMethod () { return 'ALPHA:alpha' }
  }
  class BetaFactory extends AlphaFactory {
    betaMethod () { return 'BETA:beta' }
  }
  class GammaFactory extends BetaFactory {
    alphaMethod () { return 'GAMMA:alpha' }
    gammaMethod () { return 'GAMMA:gamma' }
  }

  const factories = {
    alpha: AlphaFactory,
    beta: BetaFactory,
    gamma: GammaFactory
  }

  beforeEach(() => {
    const base = 'beta'

    builder = new Builder({ factories, base })
  })

  it('can be instantiated', () => {
    expect(builder).toBeTruthy()
  })

  it('builds a factory upon a given configuration', () => {
    const config = {
      factory: 'gamma'
    }

    const factory = builder.build(config)

    expect(factory).toBeInstanceOf(GammaFactory)
  })

  it('builds the first factory by default if no config or base given', () => {
    const builder = new Builder({ factories })

    const factory = builder.build()

    expect(factory).toBeInstanceOf(AlphaFactory)
  })

  it('builds multiple factories merging them sequentially', () => {
    const builder = new Builder({ factories })

    let factory = builder.build({ factory: 'beta,alpha' })
    expect(factory).toBeInstanceOf(BetaFactory)
    expect(factory.alphaMethod()).toEqual('ALPHA:alpha')
    expect(factory.betaMethod()).toEqual('BETA:beta')
    expect(() => factory.gammaMethod()).toThrow()

    factory = builder.build({ factory: 'alpha,beta' })
    expect(factory).toBeInstanceOf(AlphaFactory)
    expect(factory.alphaMethod()).toEqual('ALPHA:alpha')
    expect(factory.betaMethod()).toEqual('BETA:beta')
    expect(() => factory.gammaMethod()).toThrow()

    factory = builder.build({ factory: 'alpha, beta, gamma' })
    expect(factory).toBeInstanceOf(AlphaFactory)
    expect(factory.alphaMethod()).toEqual('GAMMA:alpha')
    expect(factory.betaMethod()).toEqual('BETA:beta')
    expect(factory.gammaMethod()).toEqual('GAMMA:gamma')

    factory = builder.build({ factory: 'gamma, alpha, beta' })
    expect(factory).toBeInstanceOf(AlphaFactory)
    expect(factory).toBeInstanceOf(BetaFactory)
    expect(factory).toBeInstanceOf(GammaFactory)
    expect(factory.alphaMethod()).toEqual('ALPHA:alpha')
    expect(factory.betaMethod()).toEqual('BETA:beta')
    expect(factory.gammaMethod()).toEqual('GAMMA:gamma')

    factory = builder.build({ factory: 'gamma, beta, alpha' })
    expect(factory).toBeInstanceOf(AlphaFactory)
    expect(factory).toBeInstanceOf(BetaFactory)
    expect(factory).toBeInstanceOf(GammaFactory)
    expect(factory.alphaMethod()).toEqual('ALPHA:alpha')
    expect(factory.betaMethod()).toEqual('BETA:beta')
    expect(factory.gammaMethod()).toEqual('GAMMA:gamma')
  })
})