promptfoo--promptfoo/test/util/yamlLoad.test.ts

import { describe, expect, it } from 'vitest';
import { loadYaml } from '../../src/util/yamlLoad';

describe('loadYaml', () => {
  it('parses plain YAML documents', () => {
    expect(loadYaml('a: 1\nb: hello')).toEqual({ a: 1, b: 'hello' });
  });

  it('applies YAML merge keys like js-yaml v4', () => {
    const content = [
      'defaults: &defaults',
      '  temperature: 0.5',
      '  max_tokens: 100',
      'provider:',
      '  <<: *defaults',
      '  max_tokens: 200',
    ].join('\n');

    expect(loadYaml(content)).toEqual({
      defaults: { temperature: 0.5, max_tokens: 100 },
      provider: { temperature: 0.5, max_tokens: 200 },
    });
  });

  it('preserves js-yaml v4 legacy standard tags', () => {
    expect(loadYaml('!!binary SGVsbG8=')).toEqual(new Uint8Array([72, 101, 108, 108, 111]));
    expect(loadYaml('2024-01-02')).toEqual(new Date('2024-01-02T00:00:00.000Z'));
    expect(loadYaml('!!omap [{a: 1}, {b: 2}]')).toEqual([{ a: 1 }, { b: 2 }]);
    expect(loadYaml('!!pairs [{a: 1}, {b: 2}]')).toEqual([
      ['a', 1],
      ['b', 2],
    ]);
    expect(loadYaml('!!set {a: null, b: null}')).toEqual({ a: null, b: null });
    expect(() => loadYaml('!!set {a: not-null}')).toThrow(/cannot resolve a set item/);
  });

  it('returns undefined for empty input like js-yaml v4', () => {
    expect(loadYaml('')).toBeUndefined();
  });

  it('returns undefined for whitespace-only input', () => {
    expect(loadYaml('   \n\t\n')).toBeUndefined();
  });

  it('returns undefined for comment-only input', () => {
    expect(loadYaml('# just a comment\n# another comment\n')).toBeUndefined();
  });

  it('still throws on invalid YAML', () => {
    expect(() => loadYaml('a: [unclosed')).toThrow();
  });

  it('still throws on multi-document streams like js-yaml v4 load', () => {
    expect(() => loadYaml('a: 1\n---\nb: 2')).toThrow(/single document/);
  });

  it('passes through additional load options', () => {
    expect(() => loadYaml('a: [unclosed', { filename: 'my-config.yaml' })).toThrow(
      /my-config\.yaml/,
    );
  });
});