Test 4: Validating duplicate detection...
Found 1 duplicate groups:
  - John Smith: 2 duplicate(s)
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