import { describe, it, expect } from 'vitest';
import { generateMutants, MUTATION_OPERATORS } from './mutate-operators.mjs';

describe('generateMutants', () => {
  it('флип === → !== даёт мутанта, отличного от оригинала', () => {
    const src = 'export const f = (a, b) => a === b;';
    const muts = generateMutants(src);
    expect(muts.length).toBeGreaterThan(0);
    expect(muts.every((m) => m.mutated !== src)).toBe(true);
    expect(muts.some((m) => m.mutated.includes('a !== b'))).toBe(true);
  });
  it('true → false и && → || покрыты', () => {
    const muts = generateMutants('const x = ok && ready === true;');
    expect(muts.some((m) => m.mutated.includes('ready === false'))).toBe(true);
    expect(muts.some((m) => m.mutated.includes('ok || ready'))).toBe(true);
  });
  it('нет операторных целей → пустой список (нечего мутировать)', () => {
    expect(generateMutants('const s = "plain string";')).toEqual([]);
  });
  it('детерминирован + dedup + cap (≤ MUTATION_OPERATORS.cap)', () => {
    const src = 'a === b; c === d; e === f; g === h;';
    const a = generateMutants(src);
    const b = generateMutants(src);
    expect(a).toEqual(b);
    expect(new Set(a.map((m) => m.mutated)).size).toBe(a.length);
    expect(a.length).toBeLessThanOrEqual(MUTATION_OPERATORS.cap);
  });
});