botfights/server/src/engine/arenas.test.ts

import { describe, it, expect } from 'vitest'
import { ARENAS, pickArena, randomArena } from './arenas.js'

describe('ARENAS', () => {
  it('has 40 arenas', () => {
    expect(ARENAS.length).toBe(40)
  })

  it('all arenas have required fields', () => {
    for (const arena of ARENAS) {
      expect(arena.id).toBeTruthy()
      expect(arena.name).toBeTruthy()
      expect(arena.description).toBeTruthy()
      expect(typeof arena.id).toBe('string')
      expect(typeof arena.name).toBe('string')
      expect(typeof arena.description).toBe('string')
    }
  })

  it('all arena IDs are unique', () => {
    const ids = ARENAS.map(a => a.id)
    expect(new Set(ids).size).toBe(ids.length)
  })

  it('all arena names are unique', () => {
    const names = ARENAS.map(a => a.name)
    expect(new Set(names).size).toBe(names.length)
  })

  it('arenas with modifier also have modifierDescription', () => {
    for (const arena of ARENAS) {
      if (arena.modifier) {
        expect(arena.modifierDescription).toBeTruthy()
      }
    }
  })

  it('arenas without modifier have null modifierDescription', () => {
    for (const arena of ARENAS) {
      if (!arena.modifier) {
        expect(arena.modifierDescription).toBeNull()
      }
    }
  })

  it('known modifiers are present', () => {
    const modifiers = ARENAS.map(a => a.modifier).filter(Boolean)
    expect(modifiers).toContain('speed_2x')
    expect(modifiers).toContain('roast_2x')
    expect(modifiers).toContain('food_2x')
    expect(modifiers).toContain('meme_2x')
  })
})

describe('pickArena', () => {
  it('same choices return The Singularity', () => {
    const arena = pickArena(5, 5)
    expect(arena.id).toBe('the_singularity')
  })

  it('different choices return a non-singularity arena', () => {
    const arena = pickArena(3, 7)
    expect(arena.id).not.toBe('the_singularity')
  })

  it('deterministic for same inputs', () => {
    const a1 = pickArena(10, 20)
    const a2 = pickArena(10, 20)
    expect(a1.id).toBe(a2.id)
  })

  it('different inputs give different arenas (most of the time)', () => {
    const arenas = new Set<string>()
    for (let i = 0; i < 50; i++) {
      arenas.add(pickArena(i, i + 1).id)
    }
    expect(arenas.size).toBeGreaterThan(3)
  })
})

describe('randomArena', () => {
  it('never returns The Singularity', () => {
    for (let i = 0; i < 50; i++) {
      const arena = randomArena()
      expect(arena.id).not.toBe('the_singularity')
    }
  })

  it('returns variety', () => {
    const arenas = new Set<string>()
    for (let i = 0; i < 100; i++) {
      arenas.add(randomArena().id)
    }
    expect(arenas.size).toBeGreaterThan(5)
  })

  it('returns valid arena objects', () => {
    for (let i = 0; i < 20; i++) {
      const arena = randomArena()
      expect(arena.id).toBeTruthy()
      expect(arena.name).toBeTruthy()
      expect(arena.description).toBeTruthy()
    }
  })
})