BAEL-1080 Introduction to Future in Vavr (#3372)

* Add missing features

* Add missing features

vavr/src/test/java/com/baeldung/vavr/future/FutureTest.java

@@ -59,6 +59,14 @@ public class FutureTest {
           .isEqualTo(HELLO);
     }
     
+    @Test
+    public void whenTransform_thenCorrect() {
+        Future<Object> future = Future.of(() -> 5)
+          .transformValue(result -> Try.of(() -> HELLO + result.get()));
+            
+        assertThat(future.get()).isEqualTo(HELLO + 5);
+    }
+
     @Test
     public void whenChainingCallbacks_thenCorrect() {
         Future.of(() -> HELLO)
@@ -140,6 +148,14 @@ public class FutureTest {
           .isEqualTo("Hello from Baeldung");
     }
     
+    @Test
+    public void whenCallFlatMap_thenCorrect() {
+        Future<Object> futureMap = Future.of(() -> 1)
+          .flatMap((i) -> Future.of(() -> "Hello: " + i));
+     
+        assertThat(futureMap.get()).isEqualTo("Hello: 1");
+    }
+
     @Test
     public void whenFutureFails_thenGetErrorMessage() {
         Future<String> future = Future.of(() -> "Hello".substring(-1))