Test 4: Validating duplicate detection...
Found 8 duplicate groups:
  - John Smith: 4 duplicate(s)
  - J. Smith: 2 duplicate(s)
  - Sarah Johnson: 2 duplicate(s)
  - Michael Brown: 2 duplicate(s)
  - Jennifer Davis: 1 duplicate(s)
  - Robert Wilson: 2 duplicate(s)
  - Lisa Anderson: 1 duplicate(s)
  - Thomas Clark: 2 duplicate(s)
WARNING: 'John Smith' has 4 duplicates, expected 2
WARNING: 'Sarah Johnson' has 2 duplicates, expected 1
WARNING: 'Michael Brown' has 2 duplicates, expected 1
WARNING: 'Robert Wilson' has 2 duplicates, expected 1

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