Java 9 CompletableFuture API Improvements (#1384)

core-java-9/README.md

@@ -8,3 +8,4 @@
 - [Java 9 Stream API Improvements](http://www.baeldung.com/java-9-stream-api)
 - [Java 9 Convenience Factory Methods for Collections](http://www.baeldung.com/java-9-collections-factory-methods) 
 - [New Stream Collectors in Java 9](http://www.baeldung.com/java9-stream-collectors)
+- [Java 9 CompletableFuture API Improvements](http://www.baeldung.com/java9-completablefuture-api-improvements/)

core-java-9/src/test/java/com/baeldung/java9/concurrent/future/CompletableFutureTest.java

@@ -0,0 +1,74 @@
+package com.baeldung.java9.concurrent.future;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertTrue;
+import org.junit.Test;
+
+public class CompletableFutureTest {
+    @Test
+    public void testDelay () throws Exception {
+        Object input = new Object();
+        CompletableFuture<Object> future = new CompletableFuture<>();
+        future.completeAsync(() -> input, CompletableFuture.delayedExecutor(1, TimeUnit.SECONDS));
+        
+        Thread.sleep(100);
+        
+        assertFalse(future.isDone());
+        
+        Thread.sleep(1000);
+        assertTrue(future.isDone());
+        assertSame(input, future.get());
+    }
+
+    @Test
+    public void testTimeoutTriggered () throws Exception {
+        CompletableFuture<Object> future = new CompletableFuture<>();
+        future.orTimeout(1, TimeUnit.SECONDS);
+        
+        Thread.sleep(1100);
+        
+        assertTrue(future.isDone());
+        
+        try {
+            future.get();
+        } catch (ExecutionException e) {
+            assertTrue(e.getCause() instanceof TimeoutException);
+        }
+    }
+
+    @Test
+    public void testTimeoutNotTriggered () throws Exception {
+        Object input = new Object();
+        CompletableFuture<Object> future = new CompletableFuture<>();
+        
+        future.orTimeout(1, TimeUnit.SECONDS);
+        
+        Thread.sleep(100);
+        
+        future.complete(input);
+        
+        Thread.sleep(1000);
+        
+        assertTrue(future.isDone());
+        assertSame(input, future.get());
+    }
+    
+    
+
+    @Test
+    public void completeOnTimeout () throws Exception {
+        Object input = new Object();
+        CompletableFuture<Object> future = new CompletableFuture<>();
+        future.completeOnTimeout(input, 1, TimeUnit.SECONDS);
+        
+        Thread.sleep(1100);
+        
+        assertTrue(future.isDone());
+        assertSame(input, future.get());
+    }
+}