added another test-case

also, provided a fix.

Coroutine/CoroutineHandlerInstance.cs

@@ -13,6 +13,7 @@ namespace Coroutine {
         private readonly List<ActiveCoroutine> tickingCoroutines = new List<ActiveCoroutine>();
         private readonly List<ActiveCoroutine> eventCoroutines = new List<ActiveCoroutine>();
         private readonly Queue<ActiveCoroutine> outstandingCoroutines = new Queue<ActiveCoroutine>();
+        private readonly Dictionary<int, byte> deletedCoroutinesIndexes = new Dictionary<int, byte>();
         private readonly Stopwatch stopwatch = new Stopwatch();
 
         /// <summary>
@@ -68,6 +69,7 @@ namespace Coroutine {
         /// </summary>
         /// <param name="deltaSeconds">The amount of seconds that have passed since the last time this method was invoked</param>
         public void Tick(double deltaSeconds) {
+            this.RemoveDeletedCoroutines();
             this.AddOutstandingCoroutines();
             this.tickingCoroutines.RemoveAll(c => {
                 if (c.Tick(deltaSeconds)) {
@@ -85,16 +87,15 @@ namespace Coroutine {
         /// </summary>
         /// <param name="evt">The event to raise</param>
         public void RaiseEvent(Event evt) {
-            this.AddOutstandingCoroutines();
+            for (int i = 0; i < this.eventCoroutines.Count; i++) {
-            this.eventCoroutines.RemoveAll(c => {
+                var eventCoroutine = this.eventCoroutines[i];
-                if (c.OnEvent(evt)) {
+                if (eventCoroutine.OnEvent(evt)) {
-                    return true;
+                    this.deletedCoroutinesIndexes[i] = 1;
-                } else if (!c.IsWaitingForEvent()) {
+                } else if (!eventCoroutine.IsWaitingForEvent()) {
-                    this.outstandingCoroutines.Enqueue(c);
+                    this.outstandingCoroutines.Enqueue(eventCoroutine);
-                    return true;
+                    this.deletedCoroutinesIndexes[i] = 1;
                 }
-                return false;
+            }
-            });
         }
 
         /// <summary>
@@ -114,6 +115,15 @@ namespace Coroutine {
             }
         }
 
+        private void RemoveDeletedCoroutines() {
+            int counter = 0;
+            this.eventCoroutines.RemoveAll(c => {
+                return this.deletedCoroutinesIndexes.ContainsKey(counter++);
+            });
+
+            this.deletedCoroutinesIndexes.Clear();
+        }
+
         private static IEnumerator<Wait> InvokeLaterImpl(Wait wait, Action action) {
             yield return wait;
             action();

Tests/EventBasedCoroutineTests.cs

@@ -18,8 +18,10 @@ namespace Tests {
 
             var cr = CoroutineHandler.Start(OnEventTriggered());
             Assert.AreEqual(1, counter, "instruction before yield is not executed.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(2, counter, "instruction after yield is not executed.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(2, counter, "instruction after yield is not executed.");
 
@@ -46,6 +48,7 @@ namespace Tests {
             }
 
             var cr = CoroutineHandler.Start(OnEventTriggeredInfinite());
+            CoroutineHandler.Tick(1);
             cr.OnFinished += SetCounterToUnreachableValue;
             for (var i = 0; i < 50; i++)
                 CoroutineHandler.RaiseEvent(myOtherEvent);
@@ -80,6 +83,7 @@ namespace Tests {
             }
 
             var cr = CoroutineHandler.Start(OnEvent());
+            CoroutineHandler.Tick(1);
             cr.OnFinished += SetCounterToUnreachableValue;
             for (int i = 0; i < 10; i++)
                 CoroutineHandler.RaiseEvent(myEvent);
@@ -136,21 +140,25 @@ namespace Tests {
             Assert.AreEqual(0, counterGrandParent, "Grand Parent counter is invalid at event 0.");
             Assert.AreEqual(0, counterParent, "Parent counter is invalid at event 0.");
             Assert.AreEqual(0, counterChild, "Child counter is invalid at event 0.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(1, counterAlwaysRunning, "Always running counter is invalid at event 1.");
             Assert.AreEqual(1, counterGrandParent, "Grand Parent counter is invalid at event 1.");
             Assert.AreEqual(0, counterParent, "Parent counter is invalid at event 1.");
             Assert.AreEqual(0, counterChild, "Child counter is invalid at event 1.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(2, counterAlwaysRunning, "Always running counter is invalid at event 2.");
             Assert.AreEqual(1, counterGrandParent, "Grand Parent counter is invalid at event 2.");
             Assert.AreEqual(1, counterParent, "Parent counter is invalid at event 2.");
             Assert.AreEqual(0, counterChild, "Child counter is invalid at event 2.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(3, counterAlwaysRunning, "Always running counter is invalid at event 3.");
             Assert.AreEqual(1, counterGrandParent, "Grand Parent counter is invalid at event 3.");
             Assert.AreEqual(1, counterParent, "Parent counter is invalid at event 3.");
             Assert.AreEqual(1, counterChild, "Child counter is invalid at event 3.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(4, counterAlwaysRunning, "Always running counter is invalid at event 4.");
             Assert.AreEqual(1, counterGrandParent, "Grand Parent counter is invalid at event 4.");
@@ -158,6 +166,54 @@ namespace Tests {
             Assert.AreEqual(1, counterChild, "Child counter is invalid at event 4.");
         }
 
+        [Test]
+        public void TestNestedRaiseEvent() {
+            var event1 = new Event();
+            var event2 = new Event();
+            var event3 = new Event();
+            var CoroutineCreated = new Event();
+            int counterCoroutineA = 0;
+            int counter = 0;
+
+            CoroutineHandler.Start(OnCoroutineCreatedInfinite());
+            CoroutineHandler.Start(OnEvent1());
+            CoroutineHandler.Tick(1);
+            CoroutineHandler.RaiseEvent(event1);
+            CoroutineHandler.Tick(1);
+            CoroutineHandler.RaiseEvent(event2);
+            CoroutineHandler.Tick(1);
+            CoroutineHandler.RaiseEvent(event3);
+            Assert.AreEqual(3, counter);
+            Assert.AreEqual(2, counterCoroutineA);
+
+            IEnumerator<Wait> OnCoroutineCreatedInfinite() {
+                while (true)
+                {
+                    yield return new Wait(CoroutineCreated);
+                    counterCoroutineA++;
+                }
+            }
+
+            IEnumerator<Wait> OnEvent1() {
+                yield return new Wait(event1);
+                counter++;
+                CoroutineHandler.Start(OnEvent2());
+                CoroutineHandler.RaiseEvent(CoroutineCreated);
+            }
+
+            IEnumerator<Wait> OnEvent2() {
+                yield return new Wait(event2);
+                counter++;
+                CoroutineHandler.Start(OnEvent3());
+                CoroutineHandler.RaiseEvent(CoroutineCreated);
+            }
+
+            IEnumerator<Wait> OnEvent3() {
+                yield return new Wait(event3);
+                counter++;
+            }
+        }
+
         [Test]
         public void TestPriority() {
             var myEvent = new Event();
@@ -207,6 +263,7 @@ namespace Tests {
             CoroutineHandler.Start(ShouldExecuteAfter());
             CoroutineHandler.Start(ShouldExecuteBefore0(), priority: highPriority);
             CoroutineHandler.Start(ShouldExecuteFinally(), priority: -1);
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(1, counterShouldExecuteAfter, $"ShouldExecuteAfter counter  {counterShouldExecuteAfter} is invalid.");
             Assert.AreEqual(1, counterShouldExecuteFinally, $"ShouldExecuteFinally counter  {counterShouldExecuteFinally} is invalid.");
@@ -229,6 +286,7 @@ namespace Tests {
             });
 
             Assert.AreEqual(0, counter, "Incorrect counter value after 5 seconds.");
+            CoroutineHandler.Tick(1);
             CoroutineHandler.RaiseEvent(myEvent);
             Assert.AreEqual(3, counter, "Incorrect counter value after 10 seconds.");
             Assert.AreEqual(true, cr.IsFinished, "Incorrect IsFinished value.");