diff --git a/publisher/test/LeanPipe.IntegrationTests/BasicTopicTests.cs b/publisher/test/LeanPipe.IntegrationTests/BasicTopicTests.cs
index b0bab46..dabb3d8 100644
--- a/publisher/test/LeanPipe.IntegrationTests/BasicTopicTests.cs
+++ b/publisher/test/LeanPipe.IntegrationTests/BasicTopicTests.cs
@@ -1,4 +1,3 @@
-using System.Net.Http.Json;
 using FluentAssertions;
 using LeanPipe.IntegrationTests.App;
 using LeanPipe.TestClient;
@@ -25,7 +24,7 @@ public BasicTopicTests()
     }
 
     [Fact]
-    public async Task Basic_topic_subscriber_receives_both_kinds_of_messages()
+    public async Task Subscriber_receives_both_kinds_of_notifications_when_subscribed()
     {
         var topic = new UnauthorizedTopic { TopicId = Guid.NewGuid() };
 
@@ -33,29 +32,85 @@ public async Task Basic_topic_subscriber_receives_both_kinds_of_messages()
         leanPipeClient.NotificationsOn(topic).Should().BeEmpty();
 
         var notificationTask = leanPipeClient.GetNextNotificationTaskOn(topic);
-        await httpClient.PostAsJsonAsync(
-            "/publish_unauthorized",
-            new NotificationDataDTO
-            {
+        await httpClient.PublishToUnauthorizedTopicAsync(new() {
                 TopicId = topic.TopicId,
                 Kind = NotificationKindDTO.Greeting,
                 Name = "Tester",
-            }
-        );
+            });
 
         (await notificationTask).Should()
             .BeEquivalentTo(new GreetingNotificationDTO { Greeting = "Hello Tester" });
 
         notificationTask = leanPipeClient.GetNextNotificationTaskOn(topic);
-        await httpClient.PostAsJsonAsync(
-            "/publish_unauthorized",
-            new NotificationDataDTO
-            {
-                TopicId = topic.TopicId,
-                Kind = NotificationKindDTO.Farewell,
-                Name = "Tester",
-            }
-        );
+        await httpClient.PublishToUnauthorizedTopicAsync(new() {
+            TopicId = topic.TopicId,
+            Kind = NotificationKindDTO.Farewell,
+            Name = "Tester",
+        });
+
+        (await notificationTask).Should()
+            .BeEquivalentTo(new FarewellNotificationDTO { Farewell = "Goodbye Tester" });
+
+        await leanPipeClient.UnsubscribeSuccessAsync(topic);
+
+        await httpClient.PublishToUnauthorizedTopicAsync(new() {
+            TopicId = topic.TopicId,
+            Kind = NotificationKindDTO.Farewell,
+            Name = "other Tester",
+        });
+
+        await Task.Delay(1000);
+        leanPipeClient.NotificationsOn(topic).Should().HaveCount(2);
+    }
+
+    [Fact]
+    public async Task Subscriber_does_not_receive_messages_from_other_topic_instances()
+    {
+        var topic = new UnauthorizedTopic { TopicId = Guid.NewGuid() };
+        var otherTopic = new UnauthorizedTopic { TopicId = Guid.NewGuid() };
+
+        await leanPipeClient.SubscribeSuccessAsync(topic);
+
+        await httpClient.PublishToUnauthorizedTopicAsync(new() {
+            TopicId = otherTopic.TopicId,
+            Kind = NotificationKindDTO.Greeting,
+            Name = "Tester",
+        });
+
+        await Task.Delay(1000);
+        leanPipeClient.NotificationsOn(topic).Should().BeEmpty();
+        leanPipeClient.NotificationsOn(otherTopic).Should().BeEmpty();
+
+        await leanPipeClient.UnsubscribeSuccessAsync(topic);
+    }
+
+    [Fact]
+    public async Task Resubscribing_after_disconnect_works()
+    {
+        var topic = new UnauthorizedTopic { TopicId = Guid.NewGuid() };
+
+        await leanPipeClient.SubscribeSuccessAsync(topic);
+        leanPipeClient.NotificationsOn(topic).Should().BeEmpty();
+
+        var notificationTask = leanPipeClient.GetNextNotificationTaskOn(topic);
+        await httpClient.PublishToUnauthorizedTopicAsync(new() {
+            TopicId = topic.TopicId,
+            Kind = NotificationKindDTO.Greeting,
+            Name = "Tester",
+        });
+
+        (await notificationTask).Should()
+            .BeEquivalentTo(new GreetingNotificationDTO { Greeting = "Hello Tester" });
+
+        await leanPipeClient.DisconnectAsync();
+        await leanPipeClient.SubscribeSuccessAsync(topic);
+
+        notificationTask = leanPipeClient.GetNextNotificationTaskOn(topic);
+        await httpClient.PublishToUnauthorizedTopicAsync(new() {
+            TopicId = topic.TopicId,
+            Kind = NotificationKindDTO.Farewell,
+            Name = "Tester",
+        });
 
         (await notificationTask).Should()
             .BeEquivalentTo(new FarewellNotificationDTO { Farewell = "Goodbye Tester" });
diff --git a/publisher/test/LeanPipe.IntegrationTests/PublishingExtensions.cs b/publisher/test/LeanPipe.IntegrationTests/PublishingExtensions.cs
new file mode 100644
index 0000000..f9f01b8
--- /dev/null
+++ b/publisher/test/LeanPipe.IntegrationTests/PublishingExtensions.cs
@@ -0,0 +1,27 @@
+using System.Net.Http.Json;
+using LeanPipe.IntegrationTests.App;
+
+namespace LeanPipe.IntegrationTests;
+
+public static class PublishingExtensions
+{
+    public static Task PublishToUnauthorizedTopicAsync(this HttpClient client, NotificationDataDTO notificationData)
+    {
+        return PostAsync(client, "/publish_unauthorized", notificationData);
+    }
+
+    public static Task PublishToAuthorizedTopicAsync(this HttpClient client, NotificationDataDTO notificationData)
+    {
+        return PostAsync(client, "/publish_authorized", notificationData);
+    }
+
+    private static async Task PostAsync<TPayload>(HttpClient client, string uri, TPayload payload)
+    {
+        using var response = await client.PostAsJsonAsync(
+            uri,
+            payload
+        );
+
+        response.EnsureSuccessStatusCode();
+    }
+}