diff --git a/src/test/java/com/github/tonivade/vavr/effect/IOTest.java b/src/test/java/com/github/tonivade/vavr/effect/IOTest.java
index 6fc39d2..6327c10 100644
--- a/src/test/java/com/github/tonivade/vavr/effect/IOTest.java
+++ b/src/test/java/com/github/tonivade/vavr/effect/IOTest.java
@@ -4,6 +4,7 @@
  */
 package com.github.tonivade.vavr.effect;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.junit.jupiter.api.Assertions.assertAll;
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 import static org.junit.jupiter.api.Assertions.assertEquals;
@@ -15,6 +16,12 @@
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
+
+import java.io.BufferedReader;
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.InputStreamReader;
+import java.io.PrintStream;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.time.Duration;
@@ -22,10 +29,12 @@
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import java.util.function.Consumer;
+
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+
 import io.vavr.CheckedFunction0;
 import io.vavr.CheckedFunction1;
 import io.vavr.Function1;
@@ -50,7 +59,7 @@
             pure.flatMap(string -> IO.task(() -> string.split(" "))).unsafeRunSync()),
         () -> assertEquals(Integer.valueOf(100), pure.andThen(IO.task(() -> 100)).unsafeRunSync()));
   }
-  
+
   @Test
   void asyncSuccess() {
     IO<String> async = IO.async(callback -> {
@@ -58,37 +67,53 @@
       Thread.sleep(100);
       callback.accept(Try.success("1"));
     });
-    
+
     Future<String> foldMap = IO.forked().andThen(async).runAsync();
-    
+
     assertEquals("1", foldMap.get());
   }
-  
+
   @Test
   void asyncFailure() {
     IO<String> async = IO.async(callback -> {
       Thread.sleep(100);
       callback.accept(Try.failure(new UnsupportedOperationException()));
     });
-    
+
     Future<String> foldMap = IO.forked().andThen(async).runAsync();
-   
+
     assertThrows(UnsupportedOperationException.class, foldMap::get);
   }
 
-//  @Test
-//  void echo() {
-//    IO<Unit> echo = narrowK(console.println("write your name"))
-//        .andThen(narrowK(console.readln()))
-//        .flatMap(name -> narrowK(console.println("Hello " + name)))
-//        .andThen(narrowK(console.println("end")));
-//
-//    ConsoleExecutor executor = new ConsoleExecutor().read("Toni");
-//
-//    executor.run(echo);
-//
-//    assertEquals("write your name\nHello Toni\nend\n", executor.getOutput());
-//  }
+  @Test
+  void echo() {
+    IO<Unit> echo = IO.exec(() -> System.out.println("write your name"))
+        .andThen(IO.task(() -> new BufferedReader(new InputStreamReader(System.in)).readLine()))
+        .flatMap(name -> IO.exec(() -> System.out.println("Hello " + name)))
+        .andThen(IO.exec(() -> System.out.println("end")));
+
+    var output = new ByteArrayOutputStream();
+    var savedInput = System.in;
+    var savedOutput = System.out;
+    try {
+      System.setIn(mockInput("Toni"));
+      System.setOut(mockOutput(output));
+      echo.unsafeRunSync();
+    } finally {
+      System.setIn(savedInput);
+      System.setOut(savedOutput);
+    }
+
+    assertEquals("write your name\nHello Toni\nend\n", output.toString(UTF_8));
+  }
+
+  private PrintStream mockOutput(ByteArrayOutputStream output) {
+    return new PrintStream(output);
+  }
+
+  private ByteArrayInputStream mockInput(String input) {
+    return new ByteArrayInputStream(input.getBytes(UTF_8));
+  }
 
   @Test
   void safeRunAsync() {
@@ -249,24 +274,24 @@
     assertEquals(705082704, result._2());
     assertTrue(result._1().toMillis() > 0);
   }
-  
+
   @Test
   void timeoutFail() {
     assertThrows(TimeoutException.class, IO.never().timeout(Duration.ofSeconds(1))::unsafeRunSync);
   }
-  
+
   @Test
   void timeoutSuccess() {
     assertEquals(1, IO.pure(1).timeout(Duration.ofSeconds(1)).unsafeRunSync());
   }
-  
+
   @Test
   void traverse() {
     IO<String> left = IO.task(() -> "left");
     IO<String> right = IO.task(() -> "right");
-    
+
     IO<Seq<String>> traverse = IO.traverse(List.of(left, right));
-    
+
     assertEquals(List.of("left", "right"), traverse.unsafeRunSync());
   }
 
@@ -275,9 +300,9 @@
     IO<Either<Integer, String>> race = IO.race(
         IO.delay(Duration.ofMillis(10), () -> 10),
         IO.delay(Duration.ofMillis(100), () -> "b"));
-    
+
     Either<Integer, String> orElseThrow = race.unsafeRunSync();
-    
+
     assertEquals(Either.left(10), orElseThrow);
   }
 
@@ -286,39 +311,39 @@
     IO<Either<Integer, String>> race = IO.race(
         IO.delay(Duration.ofMillis(100), () -> 10),
         IO.delay(Duration.ofMillis(10), () -> "b"));
-    
+
     Either<Integer, String> orElseThrow = race.unsafeRunSync();
-    
+
     assertEquals(Either.right("b"), orElseThrow);
   }
-  
+
   @Test
   void fork() {
     IO<String> result = IO.pure("hola")
       .flatMap(hello -> IO.delay(Duration.ofSeconds(1), () -> hello + " toni").fork())
       .flatMap(Fiber::join);
-    
+
     String orElseThrow = result.runAsync().get();
 
     assertEquals("hola toni", orElseThrow);
   }
-  
+
   @Test
   void memoize(@Mock Function1<String, String> toUpperCase) {
     when(toUpperCase.apply(any()))
-      .thenAnswer(args -> args.getArgument(0, String.class).toUpperCase());
-    
+      .thenAnswer(args -> args.<String>getArgument(0).toUpperCase());
+
     IO<Function1<String, IO<String>>> memoized = IO.memoize((String str) -> IO.pure(toUpperCase.apply(str)));
-    
+
     IO<String> flatMap = memoized.flatMap(x -> x.apply("hola"));
     flatMap.unsafeRunSync();
     flatMap.unsafeRunSync();
     flatMap.unsafeRunSync();
     flatMap.unsafeRunSync();
-    
+
     verify(toUpperCase).apply("hola");
   }
-  
+
   @Test
   void fibSyncTest() {
     assertAll(
@@ -334,7 +359,7 @@
         () -> assertEquals(6765, fibSync(20).unsafeRunSync())
         );
   }
-  
+
   @Test
   void fibAsyncTest() {
     assertAll(