content: package com.annimon.stream.streamtests;
  
  import com.annimon.stream.Functions;
  import com.annimon.stream.Stream;
  import com.annimon.stream.function.IndexedPredicate;
  import java.util.NoSuchElementException;
  import org.junit.Test;
  import static com.annimon.stream.test.hamcrest.StreamMatcher.assertElements;
  import static org.hamcrest.Matchers.contains;
  
  public final class FilterIndexedTest {
  
      @Test
      public void testFilterIndexed() {
          Stream.rangeClosed(4, 8)
                  .filterIndexed(new IndexedPredicate<Integer>() {
                      @Override
                      public boolean test(int index, Integer value) {
                          return (index * value) % 2 == 0;
                      }
                  })
                  .custom(assertElements(contains(
                         4, // (0 * 4)
                            // (1 * 5)
                         6, // (2 * 6)
                            // (3 * 7)
                         8  // (4 * 8)
                  )));
      }
  
      @Test
      public void testFilterIndexedWithStartAndStep() {
          Stream.rangeClosed(4, 8)
                  .filterIndexed(20, -5, new IndexedPredicate<Integer>() {
                      @Override
                      public boolean test(int index, Integer value) {
                          return (index * value) % 2 == 0;
                      }
                  })
                  .custom(assertElements(contains(
                         4, // (20 * 4)
                            // (15 * 5)
                         6, // (10 * 6)
                            // (5  * 7)
                         8  // (0  * 8)
                  )));
      }
  
      @Test(expected = NoSuchElementException.class)
      public void testFilterIndexedIteratorNextOnEmpty() {
          Stream.<Integer>empty()
                  .filterIndexed(IndexedPredicate.Util.wrap(Functions.remainder(2)))
                  .iterator()
                  .next();
      }
  
      @Test(expected = UnsupportedOperationException.class)
      public void testFilterIndexedIteratorRemove() {
          Stream.range(0, 10)
                  .filterIndexed(IndexedPredicate.Util.wrap(Functions.remainder(2)))
                  .iterator()
                  .remove();
      }
  }
  