added a test case for the addLast method with the future effect

jvm/src/test/scala/org/atnos/eff/FutureEffectSpec.scala

@@ -33,7 +33,8 @@ class FutureEffectSpec(implicit ee: ExecutionEnv) extends Specification with Sca
  Simple Future calls with timeout can be memoized    $e11
  Attempted Future calls with timeout can be memoized $e12
 
- TimedFuture calls can be memoized with a memo effect $e10
+ TimedFuture calls can be memoized with a memo effect $e13
+ addLast can be used to make sure an action executes when a future fails $e11
 
 
 """
@@ -158,6 +159,26 @@ class FutureEffectSpec(implicit ee: ExecutionEnv) extends Specification with Sca
     invocationsNumber must be_==(1)
   }
 
+  def e14 = {
+    type S = Fx2[TimedFuture, Option]
+    var lastActionDone = false
+
+    val action: Eff[S, Int] =
+      for {
+        i <- futureDelay[S, Int] { sleepFor(10.millis); 1 }
+        _ <- futureFail[S, Int](new Exception("boom"))
+        j =  i + 1
+      } yield j
+
+    val execute: Eff[S, Throwable Either Int] =
+      action.
+        addLast(futureDelay[S, Unit](lastActionDone = true)).
+        futureAttempt
+
+    execute.runOption.runSequential must beSome(beLeft[Throwable]).awaitFor(20.seconds)
+    lastActionDone must beTrue
+  }
+
   /**
    * HELPERS
    */