Test 4: Validating duplicate detection...
Found 6 duplicate groups:
  - John Smith: 4 duplicate(s)
  - Jane Doe: 1 duplicate(s)
  - Alan Brand: 2 duplicate(s)
  - Bob Johnson: 1 duplicate(s)
  - David Lee: 1 duplicate(s)
  - H. G.: 1 duplicate(s)
WARNING: 'John Smith' has 4 duplicates, expected 2
ERROR: Expected duplicate group for 'Sarah Johnson' not found
ERROR: Expected duplicate group for 'Michael Brown' not found
ERROR: Expected duplicate group for 'Jennifer Davis' not found
ERROR: Expected duplicate group for 'Robert Wilson' not found
ERROR: Expected duplicate group for 'Lisa Anderson' not found

ERROR: Missing 5 expected duplicate groups