splitt-the-bill/test/api/pots.test.ts

import { randomUUID } from 'node:crypto'
import { fileURLToPath } from 'node:url'
import os from 'node:os'
import path from 'node:path'
import { $fetch, setup } from '@nuxt/test-utils/e2e'
import { describe, expect, it } from 'vitest'

describe('Pot API', async () => {
  const dbPath = path.join(os.tmpdir(), `stb-test-${randomUUID()}.sqlite`)

  await setup({
    rootDir: fileURLToPath(new URL('../..', import.meta.url)),
    dev: true,
    env: { DATABASE_URL: `file:${dbPath}` },
  })

  it('creates a Pot with the creator as first participant', async () => {
    const result = await $fetch('/api/pots', {
      method: 'POST',
      body: { name: 'Weekend Trip', currency: 'eur', creatorName: 'Alice' },
    })

    expect(result.slug).toMatch(/^[a-z]+-[a-z]+-[a-z0-9]{6}$/)
    expect(result.name).toBe('Weekend Trip')
    expect(result.currency).toBe('EUR')
    expect(result.creator.name).toBe('Alice')
  })

  it('rejects Pot creation with missing fields', async () => {
    await expect(
      $fetch('/api/pots', { method: 'POST', body: { name: '', currency: 'EUR', creatorName: 'Alice' } }),
    ).rejects.toMatchObject({ statusCode: 400 })
  })

  it('adds a participant and fetches the Pot with balances', async () => {
    const pot = await $fetch('/api/pots', {
      method: 'POST',
      body: { name: 'Flat Share', currency: 'USD', creatorName: 'Alice' },
    })

    const bob = await $fetch(`/api/pots/${pot.slug}/participants`, {
      method: 'POST',
      body: { name: 'Bob' },
    })
    expect(bob.name).toBe('Bob')

    const fetched = await $fetch(`/api/pots/${pot.slug}`)
    expect(fetched.pot.slug).toBe(pot.slug)
    expect(fetched.participants).toHaveLength(2)
    expect(fetched.expenses).toEqual([])
    expect(fetched.netBalances).toEqual({
      [pot.creator.id]: 0,
      [bob.id]: 0,
    })
    expect(fetched.settlements).toEqual([])
  })

  it('supports full expense CRUD and recomputes balances', async () => {
    const pot = await $fetch('/api/pots', {
      method: 'POST',
      body: { name: 'Birthday Gift', currency: 'EUR', creatorName: 'Alice' },
    })
    const bob = await $fetch(`/api/pots/${pot.slug}/participants`, { method: 'POST', body: { name: 'Bob' } })
    const alice = pot.creator

    const expense = await $fetch(`/api/pots/${pot.slug}/expenses`, {
      method: 'POST',
      body: { description: 'Cake', amountCents: 1000, payerId: alice.id, participantIds: [alice.id, bob.id] },
    })
    expect(expense.participantIds).toEqual([alice.id, bob.id])

    let fetched = await $fetch(`/api/pots/${pot.slug}`)
    expect(fetched.expenses).toHaveLength(1)
    expect(fetched.netBalances[alice.id]).toBe(500)
    expect(fetched.netBalances[bob.id]).toBe(-500)
    expect(fetched.settlements).toEqual([{ fromId: bob.id, toId: alice.id, amountCents: 500 }])

    await $fetch(`/api/pots/${pot.slug}/expenses/${expense.id}`, {
      method: 'PATCH',
      body: { description: 'Cake', amountCents: 2000, payerId: alice.id, participantIds: [alice.id, bob.id] },
    })
    fetched = await $fetch(`/api/pots/${pot.slug}`)
    expect(fetched.netBalances[bob.id]).toBe(-1000)

    await $fetch(`/api/pots/${pot.slug}/expenses/${expense.id}`, { method: 'DELETE' })
    fetched = await $fetch(`/api/pots/${pot.slug}`)
    expect(fetched.expenses).toEqual([])
    expect(fetched.netBalances[bob.id]).toBe(0)
  })

  it('rejects an expense referencing a participant from another Pot', async () => {
    const potA = await $fetch('/api/pots', { method: 'POST', body: { name: 'A', currency: 'EUR', creatorName: 'Alice' } })
    const potB = await $fetch('/api/pots', { method: 'POST', body: { name: 'B', currency: 'EUR', creatorName: 'Zara' } })

    await expect(
      $fetch(`/api/pots/${potA.slug}/expenses`, {
        method: 'POST',
        body: { description: 'x', amountCents: 100, payerId: potB.creator.id, participantIds: [potA.creator.id] },
      }),
    ).rejects.toMatchObject({ statusCode: 400 })
  })

  it('returns 404 for an unknown Pot slug', async () => {
    await expect($fetch('/api/pots/does-not-exist-123456')).rejects.toMatchObject({ statusCode: 404 })
  })

  it('records a settlement payment as a payment-type expense and recomputes balances', async () => {
    const pot = await $fetch('/api/pots', { method: 'POST', body: { name: 'Ski Trip', currency: 'EUR', creatorName: 'Alice' } })
    const bob = await $fetch(`/api/pots/${pot.slug}/participants`, { method: 'POST', body: { name: 'Bob' } })
    const alice = pot.creator

    await $fetch(`/api/pots/${pot.slug}/expenses`, {
      method: 'POST',
      body: { description: 'Lift pass', amountCents: 1000, payerId: alice.id, participantIds: [alice.id, bob.id] },
    })

    const payment = await $fetch(`/api/pots/${pot.slug}/payments`, {
      method: 'POST',
      body: { fromId: bob.id, toId: alice.id, amountCents: 500 },
    })
    expect(payment.type).toBe('payment')
    expect(payment.payerId).toBe(bob.id)
    expect(payment.participantIds).toEqual([alice.id])

    const fetched = await $fetch(`/api/pots/${pot.slug}`)
    expect(fetched.expenses).toHaveLength(2)
    expect(fetched.expenses.filter(e => e.type === 'payment')).toHaveLength(1)
    expect(fetched.netBalances[alice.id]).toBe(0)
    expect(fetched.netBalances[bob.id]).toBe(0)
    expect(fetched.settlements).toEqual([])
  })

  it('rejects a payment with a non-positive amount or matching from/to', async () => {
    const pot = await $fetch('/api/pots', { method: 'POST', body: { name: 'Retreat', currency: 'EUR', creatorName: 'Alice' } })
    const bob = await $fetch(`/api/pots/${pot.slug}/participants`, { method: 'POST', body: { name: 'Bob' } })
    const alice = pot.creator

    await expect(
      $fetch(`/api/pots/${pot.slug}/payments`, { method: 'POST', body: { fromId: bob.id, toId: alice.id, amountCents: 0 } }),
    ).rejects.toMatchObject({ statusCode: 400 })

    await expect(
      $fetch(`/api/pots/${pot.slug}/payments`, { method: 'POST', body: { fromId: alice.id, toId: alice.id, amountCents: 100 } }),
    ).rejects.toMatchObject({ statusCode: 400 })
  })

  it('deletes a settlement payment via the regular expense delete route', async () => {
    const pot = await $fetch('/api/pots', { method: 'POST', body: { name: 'Housewarming', currency: 'EUR', creatorName: 'Alice' } })
    const bob = await $fetch(`/api/pots/${pot.slug}/participants`, { method: 'POST', body: { name: 'Bob' } })
    const alice = pot.creator

    const payment = await $fetch(`/api/pots/${pot.slug}/payments`, {
      method: 'POST',
      body: { fromId: bob.id, toId: alice.id, amountCents: 500 },
    })
    await $fetch(`/api/pots/${pot.slug}/expenses/${payment.id}`, { method: 'DELETE' })

    const fetched = await $fetch(`/api/pots/${pot.slug}`)
    expect(fetched.expenses).toEqual([])
  })

  it('sets a valid payment link on a participant and rejects an invalid one', async () => {
    const pot = await $fetch('/api/pots', { method: 'POST', body: { name: 'Reunion', currency: 'EUR', creatorName: 'Alice' } })
    const alice = pot.creator

    const updated = await $fetch(`/api/pots/${pot.slug}/participants/${alice.id}`, {
      method: 'PATCH',
      body: { paymentLink: 'https://paypal.me/alice' },
    })
    expect(updated.paymentLink).toBe('https://paypal.me/alice')

    await expect(
      $fetch(`/api/pots/${pot.slug}/participants/${alice.id}`, { method: 'PATCH', body: { paymentLink: 'javascript:alert(1)' } }),
    ).rejects.toMatchObject({ statusCode: 400 })
  })
})