test/jdk/java/util/Optional/Basic.java

*** 31,40 ****
--- 31,41 ----
  
  import java.util.List;
  import java.util.NoSuchElementException;
  import java.util.Optional;
  import java.util.concurrent.atomic.AtomicBoolean;
+ import java.util.function.Predicate;
  
  import static java.util.stream.Collectors.toList;
  
  import static org.testng.Assert.*;
  import org.testng.annotations.Test;
*** 50,59 ****
--- 51,61 ----
          assertFalse(empty.equals(Optional.of("unexpected")));
          assertFalse(Optional.of("unexpected").equals(empty));
          assertFalse(empty.equals("unexpected"));
  
          assertFalse(empty.isPresent());
+         assertTrue(empty.isEmpty());
          assertEquals(empty.hashCode(), 0);
          assertEquals(empty.orElse("x"), "x");
          assertEquals(empty.orElseGet(() -> "y"), "y");
  
          assertThrows(NoSuchElementException.class, () -> empty.get());
*** 198,203 ****
--- 200,216 ----
  
      @Test(groups = "unit")
      public void testStreamPresent() {
          assertEquals(Optional.of("xyzzy").stream().collect(toList()), List.of("xyzzy"));
      }
+ 
+     @Test(groups = "unit")
+     public void testIsEmpty() {
+         var integerList = List.of(1,2,3,4,5);
+         Predicate<Integer> isPositiveNumber =  (x -> x > 0);
+         Predicate<Integer> isNegativeNumber = (x -> x < 0);
+         Optional<Integer> positiveNumber = integerList.stream().filter(isPositiveNumber).findAny();
+         Optional<Integer> negativeNumber = integerList.stream().filter(isNegativeNumber).findAny();
+         assertFalse(positiveNumber.isEmpty());
+         assertTrue(negativeNumber.isEmpty());
+     }
  }