Replace flaky Task.Delay with TaskCompletionSource for deterministic test synchronization

- Added TaskCompletionSource fields to Spy class for each notification type
- Test handlers now signal completion through TaskCompletionSource
- Tests await TaskCompletionSource instead of arbitrary delays
- Eliminates timing-dependent flakiness in CI systems

Co-authored-by: KnibbsyMan <23156317+KnibbsyMan@users.noreply.github.com>

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/WorkflowDispatchNotifications/Spy.cs

@@ -5,6 +5,11 @@ namespace Elsa.Workflows.IntegrationTests.Scenarios.WorkflowDispatchNotification
 
 public class Spy
 {
+    private readonly TaskCompletionSource<bool> _workflowDefinitionDispatchingTcs = new();
+    private readonly TaskCompletionSource<bool> _workflowDefinitionDispatchedTcs = new();
+    private readonly TaskCompletionSource<bool> _workflowInstanceDispatchingTcs = new();
+    private readonly TaskCompletionSource<bool> _workflowInstanceDispatchedTcs = new();
+
     public bool WorkflowDefinitionDispatchingWasCalled { get; set; }
     public bool WorkflowDefinitionDispatchedWasCalled { get; set; }
     public bool WorkflowInstanceDispatchingWasCalled { get; set; }
@@ -13,4 +18,14 @@ public class Spy
     public DispatchWorkflowDefinitionRequest? CapturedDefinitionRequest { get; set; }
     public DispatchWorkflowInstanceRequest? CapturedInstanceRequest { get; set; }
     public DispatchWorkflowResponse? CapturedResponse { get; set; }
+
+    public Task WaitForWorkflowDefinitionDispatchingAsync() => _workflowDefinitionDispatchingTcs.Task;
+    public Task WaitForWorkflowDefinitionDispatchedAsync() => _workflowDefinitionDispatchedTcs.Task;
+    public Task WaitForWorkflowInstanceDispatchingAsync() => _workflowInstanceDispatchingTcs.Task;
+    public Task WaitForWorkflowInstanceDispatchedAsync() => _workflowInstanceDispatchedTcs.Task;
+
+    public void SignalWorkflowDefinitionDispatching() => _workflowDefinitionDispatchingTcs.TrySetResult(true);
+    public void SignalWorkflowDefinitionDispatched() => _workflowDefinitionDispatchedTcs.TrySetResult(true);
+    public void SignalWorkflowInstanceDispatching() => _workflowInstanceDispatchingTcs.TrySetResult(true);
+    public void SignalWorkflowInstanceDispatched() => _workflowInstanceDispatchedTcs.TrySetResult(true);
 }

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/WorkflowDispatchNotifications/TestHandler.cs

@@ -20,6 +20,7 @@ public class TestHandler :
     {
         _spy.WorkflowDefinitionDispatchingWasCalled = true;
         _spy.CapturedDefinitionRequest = notification.Request;
+        _spy.SignalWorkflowDefinitionDispatching();
         return Task.CompletedTask;
     }
 
@@ -27,6 +28,7 @@ public class TestHandler :
     {
         _spy.WorkflowDefinitionDispatchedWasCalled = true;
         _spy.CapturedResponse = notification.Response;
+        _spy.SignalWorkflowDefinitionDispatched();
         return Task.CompletedTask;
     }
 
@@ -34,6 +36,7 @@ public class TestHandler :
     {
         _spy.WorkflowInstanceDispatchingWasCalled = true;
         _spy.CapturedInstanceRequest = notification.Request;
+        _spy.SignalWorkflowInstanceDispatching();
         return Task.CompletedTask;
     }
 
@@ -41,6 +44,7 @@ public class TestHandler :
     {
         _spy.WorkflowInstanceDispatchedWasCalled = true;
         _spy.CapturedResponse = notification.Response;
+        _spy.SignalWorkflowInstanceDispatched();
         return Task.CompletedTask;
     }
 }

test/integration/Elsa.Workflows.IntegrationTests/Scenarios/WorkflowDispatchNotifications/Tests.cs

@@ -43,8 +43,9 @@ public class Tests
         // Act
         await _workflowDispatcher.DispatchAsync(request, null);
 
-        // Allow async notification handlers to complete
-        await Task.Delay(100);
+        // Wait for notification handlers to complete
+        await _spy.WaitForWorkflowDefinitionDispatchingAsync();
+        await _spy.WaitForWorkflowDefinitionDispatchedAsync();
 
         // Assert
         Assert.True(_spy.WorkflowDefinitionDispatchingWasCalled, "WorkflowDefinitionDispatching notification should be called");
@@ -70,8 +71,9 @@ public class Tests
         // Act
         await _workflowDispatcher.DispatchAsync(request, null);
 
-        // Allow async notification handlers to complete
-        await Task.Delay(100);
+        // Wait for notification handlers to complete
+        await _spy.WaitForWorkflowInstanceDispatchingAsync();
+        await _spy.WaitForWorkflowInstanceDispatchedAsync();
 
         // Assert
         Assert.True(_spy.WorkflowInstanceDispatchingWasCalled, "WorkflowInstanceDispatching notification should be called");