public/js/tests/is-winner_test.js

const db = (() => {
  //countries that won the FIFA World Cup
  const countries = [
    { id: 1, name: 'Brazil', continent: 'South America' },
    { id: 2, name: 'Germany', continent: 'Europe' },
    { id: 3, name: 'Italy', continent: 'Europe' },
    { id: 4, name: 'Argentina', continent: 'South America' },
    { id: 5, name: 'France', continent: 'Europe' },
    { id: 6, name: 'Uruguay', continent: 'South America' },
    { id: 7, name: 'England', continent: 'Europe' },
    { id: 8, name: 'Spain', continent: 'Europe' },
  ]

  //Information about the wins
  const results = [
    { id: 1, countryId: 6, year: 1930, score: '4-2' },
    { id: 2, countryId: 3, year: 1934, score: '2-1' },
    { id: 3, countryId: 3, year: 1938, score: '4-2' },
    { id: 4, countryId: 6, year: 1950, score: '2-1' },
    { id: 5, countryId: 2, year: 1954, score: '3-2' },
    { id: 6, countryId: 1, year: 1958, score: '5-2' },
    { id: 7, countryId: 1, year: 1962, score: '3-1' },
    { id: 8, countryId: 7, year: 1966, score: '4-2' },
    { id: 9, countryId: 1, year: 1970, score: '4-1' },
    { id: 10, countryId: 2, year: 1974, score: '2-1' },
    { id: 11, countryId: 4, year: 1978, score: '3-1' },
    { id: 12, countryId: 3, year: 1982, score: '3-1' },
    { id: 13, countryId: 4, year: 1986, score: '3-2' },
    { id: 14, countryId: 2, year: 1990, score: '1-0' },
    { id: 15, countryId: 1, year: 1994, score: '3-2p' },
    { id: 16, countryId: 5, year: 1998, score: '3-0' },
    { id: 17, countryId: 1, year: 2002, score: '2-0' },
    { id: 18, countryId: 3, year: 2006, score: '5-3p' },
    { id: 19, countryId: 8, year: 2010, score: '1-0' },
    { id: 20, countryId: 2, year: 2014, score: '1-0' },
    { id: 21, countryId: 5, year: 2018, score: '4-2' },
  ]

  return {
    //returns the information of the country
    getWinner: async (countryName) => {
      const match = countries.find((country) => country.name === countryName)
      if (!match) throw Error('Country Not Found')
      return match
    },
    //returns the information of the wins of that country
    getResults: async (countryId) => {
      const match = results.filter((result) => result.countryId === countryId)
      if (!match.length) throw Error('Results Not Found')
      return match
    },
    addCountry: (country) => countries.push(country),
    addResults: (result) => results.push(result),
  }
})()
// /*/ // ⚡
export const tests = []
const t = (f) => tests.push(f)

t(async ({ eq }) =>
  // testing correct continent but wrong number of times
  eq(
    await isWinner('England'),
    'England is not what we are looking for because of the number of times it was champion'
  )
)

t(async ({ eq }) =>
  // testing non winner country
  eq(await isWinner('Colombia'), 'Colombia never was a winner')
)

t(async ({ eq }) =>
  // testing wrong continent country
  eq(
    await isWinner('Uruguay'),
    'Uruguay is not what we are looking for because of the continent'
  )
)

t(async ({ eq }) =>
  // testing no country
  eq(await isWinner(''), ' never was a winner')
)

t(async ({ eq }) =>
  // testing correct number of times but wrong continent
  eq(
    await isWinner('Brazil'),
    'Brazil is not what we are looking for because of the continent'
  )
)

t(async ({ eq }) =>
  // testing correct number of times and correct continent
  eq(
    await isWinner('Germany'),
    'Germany won the FIFA World Cup in 1954, 1974, 1990, 2014 winning by 3-2, 2-1, 1-0, 1-0'
  )
)

t(async ({ eq, ctx }) =>
  // testing correct number of times and correct continent, for the fake country
  eq(
    await isWinner(ctx.name),
    `${ctx.name} won the FIFA World Cup in 2022, 2026, 2030 winning by 1-0, 3-1, 2-1`
  )
)

Object.freeze(tests)

export const setup = () => {
  const seed = Math.random()
  const name = seed.toString(36).slice(2)

  db.addCountry({ id: 9, name, continent: 'Europe' })
  db.addResults({ countryId: 9, year: 2022, score: '1-0' })
  db.addResults({ countryId: 9, year: 2026, score: '3-1' })
  db.addResults({ countryId: 9, year: 2030, score: '2-1' })

  return { name }
}