Test 4: Validating duplicate detection...
Found 3 duplicate groups:
  - John Smith: 1 duplicate(s)
  - Sarah Johnson: 1 duplicate(s)
  - Robert Wilson: 1 duplicate(s)
WARNING: 'John Smith' has 1 duplicates, expected 2
ERROR: Expected duplicate group for 'Michael Brown' not found
ERROR: Expected duplicate group for 'Jennifer Davis' not found
ERROR: Expected duplicate group for 'Lisa Anderson' not found

ERROR: Missing 3 expected duplicate groups