Test 4: Validating duplicate detection...
Found 7 duplicate groups:
  - Alice Johnson: 2 duplicate(s)
  - Emma Wilson: 2 duplicate(s)
  - Frank Brown: 2 duplicate(s)
  - Henry Davis: 2 duplicate(s)
  - Jack Anderson: 2 duplicate(s)
  - John Smith: 2 duplicate(s)
  - Thomas Clark: 1 duplicate(s)
WARNING: 'Sarah Johnson' has 2 duplicates, expected 1
WARNING: 'Michael Brown' has 2 duplicates, expected 1
WARNING: 'Jennifer Davis' has 2 duplicates, expected 1
WARNING: 'Robert Wilson' has 2 duplicates, expected 1
WARNING: 'Lisa Anderson' has 2 duplicates, expected 1

✓ All expected duplicate groups found
WARNING: Unusual match reason: 'name_and_phone' (not in standard list)
WARNING: Unusual match reason: 'email_and_name_and_phone' (not in standard list)
✓ Match reasons look reasonable
SUCCESS: Duplicate detection validated!