Fix and optimize RequestsCookieJar.multiple_domains() method

[tboy1337]

Summary

Refactors the multiple_domains() method in RequestsCookieJar to fix a logic bug and improve performance by using a set for domain tracking instead of a list.

Changes

• Fixed bug: The previous implementation incorrectly returned True when encountering duplicate domains. The method now correctly checks for multiple unique domains
• Performance improvement: Changed from list to set for O(1) domain lookups instead of O(n)
• Simplified logic: More readable implementation that counts unique domains and checks if count > 1
• Comprehensive tests: Added 8 new unit tests covering various scenarios:
  • Empty jar
  • Single domain with multiple cookies
  • Multiple unique domains
  • Duplicate domains (should count as single)
  • Mixed duplicates and unique domains
  • Edge cases with empty string domains

Files Changed

• src/requests/cookies.py: Refactored multiple_domains() method (4 lines modified)
• tests/test_requests.py: Added 65 lines of comprehensive unit tests

Testing

All new tests pass and verify the correct behavior of the method across various domain scenarios.

Type of Change

• [x] Bug fix (non-breaking change which fixes an issue)
• [x] Performance improvement
• [x] Test coverage improvement

demonstrate_bug.py