// lib/merge-gitignore.test.mjs
import { test } from 'node:test'
import assert from 'node:assert/strict'
import { mergeGitignore } from './merge-gitignore.mjs'

test('union dedupes and preserves base order, appends new', () => {
  const base = 'node_modules\n.env\n'
  const add = '.env\ndist\n.DS_Store\n'
  assert.equal(mergeGitignore(base, add), 'node_modules\n.env\ndist\n.DS_Store\n')
})

test('blank lines and comments in add are ignored for dedupe but kept once', () => {
  assert.equal(mergeGitignore('a\n', '\n# c\nb\n'), 'a\n# c\nb\n')
})