Test 4: Validating duplicate detection...
Found 7 duplicate groups:
  - John Smith: 1 duplicate(s)
  - Sarah Johnson: 0 duplicate(s)
  - Michael Brown: 1 duplicate(s)
  - Jennifer Davis: 1 duplicate(s)
  - Robert Wilson: 0 duplicate(s)
  - Lisa Anderson: 1 duplicate(s)
  - Thomas Clark: 1 duplicate(s)
WARNING: 'John Smith' has 1 duplicates, expected 2
WARNING: 'Sarah Johnson' has 0 duplicates, expected 1
WARNING: 'Robert Wilson' has 0 duplicates, expected 1

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