?TreeSet? Comparators not correctly comparing everything - Compares only a subset

import java.util.logging.Logger;
import org.junit.*;

class Breaker {
   static Logger log = Logger.getLogger(getName())
   
   @Test
   void testBreaking() {
      def comparator = [compare:
         {a,b-> 
            def retVal = a.x.compareTo(b.x)
            log.info("Comparing ${a.x} to ${b.x} and returning ${retVal}")
            return retVal }
      ] as Comparator
   
      def ts1 = new TreeSet(comparator)
      ts1.addAll([
         new ToCompare(x:"1"),
         new ToCompare(x:"2"),
         new ToCompare(x:"3")
      ])
       
      def ts2 = new TreeSet(comparator)
      ts2.addAll([
         new ToCompare(x:"1"),
         new ToCompare(x:"2"),
         new ToCompare(x:"3")
      ])
      
      def difference = ts1 - ts2
      assert difference.size() == 0
   }
}

class ToCompare {
   String x
}

Sep 29, 2011 9:03:57 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 2 to 1 and returning 1
Sep 29, 2011 9:03:57 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 1 and returning 2
Sep 29, 2011 9:03:57 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 2 and returning 1
Sep 29, 2011 9:03:57 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 2 to 1 and returning 1
Sep 29, 2011 9:03:57 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 1 and returning 2
Sep 29, 2011 9:03:57 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 2 and returning 1

Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 2 to 1 and returning 1
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 1 and returning 2
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 2 and returning 1
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 2 to 1 and returning 1
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 1 and returning 2
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 2 and returning 1
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 1 to 2 and returning -1
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 1 to 1 and returning 0
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 2 to 2 and returning 0
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 2 and returning 1
Sep 29, 2011 9:07:09 PM sun.reflect.NativeMethodAccessorImpl invoke0
INFO: Comparing 3 to 3 and returning 0