=== 测试国家验证（不区分大小写） ===
输入: 'gb' -> 结果: 'United Kingdom' 预期: 'United Kingdom' ✓
输入: 'GB' -> 结果: 'United Kingdom' 预期: 'United Kingdom' ✓
输入: 'Gb' -> 结果: 'United Kingdom' 预期: 'United Kingdom' ✓
输入: 'uk' -> 结果: 'NULL' 预期: 'United Kingdom' ✗
  错误: 预期 'United Kingdom', 实际 'NULL'
输入: 'UK' -> 结果: 'NULL' 预期: 'United Kingdom' ✗
  错误: 预期 'United Kingdom', 实际 'NULL'
输入: 'united kingdom' -> 结果: 'United Kingdom' 预期: 'United Kingdom' ✓
输入: 'United Kingdom' -> 结果: 'United Kingdom' 预期: 'United Kingdom' ✓
输入: 'UNITED KINGDOM' -> 结果: 'United Kingdom' 预期: 'United Kingdom' ✓
输入: 'cn' -> 结果: 'China' 预期: 'China' ✓
输入: 'CN' -> 结果: 'China' 预期: 'China' ✓
输入: 'china' -> 结果: 'China' 预期: 'China' ✓
输入: 'China' -> 结果: 'China' 预期: 'China' ✓
输入: 'CHINA' -> 结果: 'China' 预期: 'China' ✓

=== 测试电话号码空格处理 ===
输入: '86 17781686790'
  去空格: '8617781686790'
  只保留数字: '8617781686790'
  预期: '8617781686790' ✓
---
输入: '86  17781686790'
  去空格: '8617781686790'
  只保留数字: '8617781686790'
  预期: '8617781686790' ✓
---
输入: ' 86 17781686790 '
  去空格: '8617781686790'
  只保留数字: '8617781686790'
  预期: '8617781686790' ✓
---
输入: '86-17781686790'
  去空格: '86-17781686790'
  只保留数字: '8617781686790'
  预期: '8617781686790' ✓
---
输入: '86(177)81686790'
  去空格: '86(177)81686790'
  只保留数字: '8617781686790'
  预期: '8617781686790' ✓
---
输入: '+86 177 8168 6790'
  去空格: '+8617781686790'
  只保留数字: '8617781686790'
  预期: '8617781686790' ✓
---

=== 测试空值验证 ===
输入: null -> empty(): true
输入: spaces only -> empty(): false

测试完成！