oil-formula-calculator/frontend/cypress/e2e/recipe-cost-parity.cy.js

describe('Recipe Cost Parity Test', () => {
  // Verify recipe cost formula: cost = sum(bottle_price / drop_count * drops)

  let oilsMap = {}
  let testRecipes = []

  before(() => {
    cy.request('/api/oils').then(res => {
      res.body.forEach(oil => {
        oilsMap[oil.name] = {
          bottle_price: oil.bottle_price,
          drop_count: oil.drop_count,
          ppd: oil.drop_count ? oil.bottle_price / oil.drop_count : 0,
          retail_price: oil.retail_price
        }
      })
    })
    cy.request('/api/recipes').then(res => {
      testRecipes = res.body.slice(0, 20)
    })
  })

  it('oil data has correct structure (100+ oils)', () => {
    expect(Object.keys(oilsMap).length).to.be.gte(100)
  })

  it('price-per-drop matches formula for available oils', () => {
    const checks = ['薰衣草', '乳香', '茶树', '柠檬', '椒样薄荷']
    checks.forEach(name => {
      const oil = oilsMap[name]
      if (oil) {
        const expected = oil.bottle_price / oil.drop_count
        expect(oil.ppd).to.be.closeTo(expected, 0.0001)
      }
    })
  })

  it('calculates cost for each of first 20 recipes', () => {
    testRecipes.forEach(recipe => {
      let cost = 0
      recipe.ingredients.forEach(ing => {
        const oil = oilsMap[ing.oil_name]
        if (oil) cost += oil.ppd * ing.drops
      })
      expect(cost).to.be.gte(0)
    })
  })

  it('retail price >= wholesale for oils that have it', () => {
    Object.entries(oilsMap).forEach(([name, oil]) => {
      if (oil.retail_price && oil.retail_price > 0) {
        expect(oil.retail_price).to.be.gte(oil.bottle_price)
      }
    })
  })

  it('no recipe has all-zero cost', () => {
    if (testRecipes.length === 0) return
    let zeroCostCount = 0
    testRecipes.forEach(recipe => {
      let cost = 0
      recipe.ingredients.forEach(ing => {
        const oil = oilsMap[ing.oil_name]
        if (oil) cost += oil.ppd * ing.drops
      })
      if (cost === 0) zeroCostCount++
    })
    expect(zeroCostCount).to.be.lt(testRecipes.length)
  })

  it('cost formula is consistent: two calculation methods agree', () => {
    testRecipes.forEach(recipe => {
      const costs = recipe.ingredients.map(ing => {
        const oil = oilsMap[ing.oil_name]
        return oil ? oil.ppd * ing.drops : 0
      })
      const fromMap = costs.reduce((a, b) => a + b, 0)
      const fromReduce = recipe.ingredients.reduce((s, ing) => {
        const oil = oilsMap[ing.oil_name]
        return s + (oil ? oil.ppd * ing.drops : 0)
      }, 0)
      expect(fromMap).to.be.closeTo(fromReduce, 0.001)
    })
  })
})