diff --git a/up-subscription/src/handlers/fetch_subscribers.rs b/up-subscription/src/handlers/fetch_subscribers.rs
index 60cb3f5..035732d 100644
--- a/up-subscription/src/handlers/fetch_subscribers.rs
+++ b/up-subscription/src/handlers/fetch_subscribers.rs
@@ -61,9 +61,10 @@ impl RequestHandler for FetchSubscribersRequestHandler {
             ));
         };
 
-        // topic input validation
         // [impl->dsn~usubscription-fetch-subscribers-invalid-topic~1]
-        helpers::validate_uri(&topic)?;
+        helpers::validate_uri(&topic).map_err(|e| {
+            ServiceInvocationError::InvalidArgument(format!("Invalid topic uri '{topic}': {e}"))
+        })?;
 
         // Interact with subscription manager backend
         let (respond_to, receive_from) = oneshot::channel::<Vec<SubscriberUUri>>();
@@ -187,11 +188,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -216,11 +213,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -242,11 +235,7 @@ mod tests {
             .handle_request(RESOURCE_ID_FETCH_SUBSCRIBERS, &message_attributes, None)
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -275,11 +264,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     // [utest->dsn~usubscription-fetch-subscribers-invalid-topic~1]
@@ -329,10 +314,6 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 }
diff --git a/up-subscription/src/handlers/fetch_subscriptions.rs b/up-subscription/src/handlers/fetch_subscriptions.rs
index a747bf1..61ebe04 100644
--- a/up-subscription/src/handlers/fetch_subscriptions.rs
+++ b/up-subscription/src/handlers/fetch_subscriptions.rs
@@ -62,13 +62,21 @@ impl RequestHandler for FetchSubscriptionsRequestHandler {
         let request_kind = match request {
             Some(Request::Topic(topic)) => {
                 // [impl->dsn~usubscription-fetch-subscriptions-invalid-topic~1]
-                helpers::validate_uri(&topic)?;
+                helpers::validate_uri(&topic).map_err(|e| {
+                    ServiceInvocationError::InvalidArgument(format!(
+                        "Invalid topic uri '{topic}': {e}"
+                    ))
+                })?;
                 RequestKind::Topic(topic)
             }
             Some(Request::Subscriber(subscriber)) => {
                 if let Some(subscriber) = subscriber.uri.into_option() {
                     // [impl->dsn~usubscription-fetch-subscriptions-invalid-subscriber~1]
-                    helpers::validate_uri(&subscriber)?;
+                    helpers::validate_uri(&subscriber).map_err(|e| {
+                        ServiceInvocationError::InvalidArgument(format!(
+                            "Invalid subscriber uri '{subscriber}': {e}"
+                        ))
+                    })?;
                     RequestKind::Subscriber(subscriber)
                 } else {
                     return Err(ServiceInvocationError::InvalidArgument(
@@ -235,11 +243,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -264,11 +268,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -290,11 +290,7 @@ mod tests {
             .handle_request(RESOURCE_ID_FETCH_SUBSCRIPTIONS, &message_attributes, None)
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -323,11 +319,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     // [utest->dsn~usubscription-fetch-subscriptions-invalid-subscriber~1]
@@ -386,11 +378,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     // [utest->dsn~usubscription-fetch-subscriptions-invalid-topic~1]
@@ -444,10 +432,6 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 }
diff --git a/up-subscription/src/handlers/register_for_notifications.rs b/up-subscription/src/handlers/register_for_notifications.rs
index c35bb02..fa86afe 100644
--- a/up-subscription/src/handlers/register_for_notifications.rs
+++ b/up-subscription/src/handlers/register_for_notifications.rs
@@ -58,6 +58,10 @@ impl RequestHandler for RegisterNotificationsRequestHandler {
                 "No topic defined in request".to_string(),
             ));
         };
+        // [impl->dsn~usubscription-register-notifications-invalid-topic~1]
+        helpers::validate_uri(topic).map_err(|e| {
+            ServiceInvocationError::InvalidArgument(format!("Invalid topic uri '{topic}': {e}"))
+        })?;
 
         // Interact with notification manager backend
         let se = NotificationEvent::AddNotifyee {
@@ -84,8 +88,11 @@ impl RequestHandler for RegisterNotificationsRequestHandler {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use test_case::test_case;
     use tokio::sync::mpsc::{self};
 
+    use up_rust::UUri;
+
     use crate::{helpers, tests::test_lib};
 
     // [utest->dsn~usubscription-register-notifications-protobuf~1]
@@ -162,11 +169,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -192,11 +195,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -221,11 +220,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -253,10 +248,59 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
+    }
+
+    // [utest->dsn~usubscription-register-notifications-invalid-topic~1]
+    #[test_case(UUri::default(); "Bad topic UUri")]
+    #[test_case(UUri {
+            authority_name: String::from("*"),
+            ue_id: test_lib::helpers::TOPIC_LOCAL1_ID,
+            ue_version_major: test_lib::helpers::TOPIC_LOCAL1_VERSION as u32,
+            resource_id: test_lib::helpers::TOPIC_LOCAL1_RESOURCE as u32,
+            ..Default::default()
+        }; "Wildcard authority in topic UUri")]
+    #[test_case(UUri {
+            authority_name: test_lib::helpers::LOCAL_AUTHORITY.into(),
+            ue_id: 0xFFFF_0000,
+            ue_version_major: test_lib::helpers::TOPIC_LOCAL1_VERSION as u32,
+            resource_id: test_lib::helpers::TOPIC_LOCAL1_RESOURCE as u32,
+            ..Default::default()
+        }; "Wildcard entity id in topic UUri")]
+    #[test_case(UUri {
+            authority_name: test_lib::helpers::LOCAL_AUTHORITY.into(),
+            ue_id: test_lib::helpers::TOPIC_LOCAL1_ID,
+            ue_version_major: test_lib::helpers::TOPIC_LOCAL1_VERSION as u32,
+            resource_id: 0x0000_FFFF,
+            ..Default::default()
+        }; "Wildcard resource id in topic UUri")]
+    #[tokio::test]
+    async fn test_invalid_topic_uri(topic: UUri) {
+        helpers::init_once();
+
+        // create request and other required object(s)
+        let notification_request = NotificationsRequest {
+            topic: Some(topic).into(),
+            ..Default::default()
+        };
+        let request_payload = UPayload::try_from_protobuf(notification_request.clone()).unwrap();
+        let message_attributes = UAttributes {
+            source: Some(test_lib::helpers::subscriber_uri1()).into(),
+            ..Default::default()
+        };
+        let (notification_sender, _) = mpsc::channel::<NotificationEvent>(1);
+
+        // create and spawn off handler, to make all the asnync goodness work
+        let request_handler = RegisterNotificationsRequestHandler::new(notification_sender);
+
+        let result = request_handler
+            .handle_request(
+                RESOURCE_ID_REGISTER_FOR_NOTIFICATIONS,
+                &message_attributes,
+                Some(request_payload),
+            )
+            .await;
+
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 }
diff --git a/up-subscription/src/handlers/subscribe.rs b/up-subscription/src/handlers/subscribe.rs
index 2e64996..f879195 100644
--- a/up-subscription/src/handlers/subscribe.rs
+++ b/up-subscription/src/handlers/subscribe.rs
@@ -206,11 +206,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -235,11 +231,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -261,11 +253,7 @@ mod tests {
             .handle_request(RESOURCE_ID_SUBSCRIBE, &message_attributes, None)
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -294,11 +282,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
diff --git a/up-subscription/src/handlers/unregister_for_notifications.rs b/up-subscription/src/handlers/unregister_for_notifications.rs
index 3a59ca3..b7753a6 100644
--- a/up-subscription/src/handlers/unregister_for_notifications.rs
+++ b/up-subscription/src/handlers/unregister_for_notifications.rs
@@ -155,11 +155,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -185,11 +181,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -214,11 +206,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -246,10 +234,6 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 }
diff --git a/up-subscription/src/handlers/unsubscribe.rs b/up-subscription/src/handlers/unsubscribe.rs
index ae7476a..4c9dc28 100644
--- a/up-subscription/src/handlers/unsubscribe.rs
+++ b/up-subscription/src/handlers/unsubscribe.rs
@@ -180,11 +180,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -209,11 +205,7 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -235,11 +227,7 @@ mod tests {
             .handle_request(RESOURCE_ID_UNSUBSCRIBE, &message_attributes, None)
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 
     #[tokio::test]
@@ -268,10 +256,6 @@ mod tests {
             )
             .await;
 
-        assert!(result.is_err());
-        match result.unwrap_err() {
-            ServiceInvocationError::InvalidArgument(_) => {}
-            _ => panic!("Wrong error type"),
-        }
+        assert!(result.is_err_and(|err| matches!(err, ServiceInvocationError::InvalidArgument(_))));
     }
 }