test/java/util/stream/test/org/openjdk/tests/java/util/stream/TabulatorsTest.java

rev 7827 : 8019401: Collectors.collectingAndThen
Reviewed-by:
Contributed-by: brian.goetz@oracle.com

*** 23,32 ****
--- 23,33 ----
  package org.openjdk.tests.java.util.stream;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
+ import java.util.Collections;
  import java.util.Comparator;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
*** 50,59 ****
--- 51,61 ----
  import java.util.stream.StreamTestDataProvider;
  import java.util.stream.TestData;
  
  import org.testng.annotations.Test;
  
+ import static java.util.stream.Collectors.collectingAndThen;
  import static java.util.stream.Collectors.groupingBy;
  import static java.util.stream.Collectors.groupingByConcurrent;
  import static java.util.stream.Collectors.partitioningBy;
  import static java.util.stream.Collectors.reducing;
  import static java.util.stream.Collectors.toCollection;
*** 601,606 ****
--- 603,621 ----
          exerciseMapTabulation(data,
                                partitioningBy(classifier, reducing(0, Integer::sum)),
                                new PartitionAssertion<>(classifier,
                                                         new ReduceAssertion<>(0, LambdaTestHelpers.identity(), Integer::sum)));
      }
+ 
+     @Test(dataProvider = "StreamTestData<Integer>", dataProviderClass = StreamTestDataProvider.class)
+     public void testComposeFinisher(String name, TestData.OfRef<Integer> data) throws ReflectiveOperationException {
+         List<Integer> asList = exerciseTerminalOps(data, s -> s.collect(toList()));
+         List<Integer> asImmutableList = exerciseTerminalOps(data, s -> s.collect(collectingAndThen(toList(), Collections::unmodifiableList)));
+         assertEquals(asList, asImmutableList);
+         try {
+             asImmutableList.add(0);
+             fail("Expecting immutable result");
+         }
+         catch (UnsupportedOperationException ignored) { }
+     }
+ 
  }