diff --git a/src/error.rs b/src/error.rs
index 8cfa3181..3bb8a4cb 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -279,7 +279,7 @@ pub enum DialError {
 }
 
 /// Dialing resulted in an immediate error before performing any network operations.
-#[derive(Debug, thiserror::Error)]
+#[derive(Debug, thiserror::Error, Copy, Clone, Eq, PartialEq)]
 pub enum ImmediateDialError {
     /// The provided address does not include a peer ID.
     #[error("`PeerId` missing from the address")]
diff --git a/src/mock/substream.rs b/src/mock/substream.rs
index b1308abb..4c52394e 100644
--- a/src/mock/substream.rs
+++ b/src/mock/substream.rs
@@ -18,7 +18,7 @@
 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-use crate::error::{Error, SubstreamError};
+use crate::error::SubstreamError;
 
 use bytes::{Bytes, BytesMut};
 use futures::{Sink, Stream};
diff --git a/src/protocol/libp2p/kademlia/executor.rs b/src/protocol/libp2p/kademlia/executor.rs
index a2e99adb..c2a04bf9 100644
--- a/src/protocol/libp2p/kademlia/executor.rs
+++ b/src/protocol/libp2p/kademlia/executor.rs
@@ -259,10 +259,9 @@ mod tests {
         let mut executor = QueryExecutor::new();
         let peer = PeerId::random();
         let mut substream = MockSubstream::new();
-        substream
-            .expect_poll_next()
-            .times(1)
-            .return_once(|_| Poll::Ready(Some(Err(crate::Error::Unknown))));
+        substream.expect_poll_next().times(1).return_once(|_| {
+            Poll::Ready(Some(Err(crate::error::SubstreamError::ConnectionClosed)))
+        });
 
         executor.read_message(
             peer,
@@ -294,10 +293,9 @@ mod tests {
         substream.expect_poll_ready().times(1).return_once(|_| Poll::Ready(Ok(())));
         substream.expect_start_send().times(1).return_once(|_| Ok(()));
         substream.expect_poll_flush().times(1).return_once(|_| Poll::Ready(Ok(())));
-        substream
-            .expect_poll_next()
-            .times(1)
-            .return_once(|_| Poll::Ready(Some(Err(crate::Error::Unknown))));
+        substream.expect_poll_next().times(1).return_once(|_| {
+            Poll::Ready(Some(Err(crate::error::SubstreamError::ConnectionClosed)))
+        });
 
         executor.send_request_read_response(
             peer,
@@ -330,7 +328,7 @@ mod tests {
         substream
             .expect_poll_ready()
             .times(1)
-            .return_once(|_| Poll::Ready(Err(crate::Error::Unknown)));
+            .return_once(|_| Poll::Ready(Err(crate::error::SubstreamError::ConnectionClosed)));
         substream.expect_poll_close().times(1).return_once(|_| Poll::Ready(Ok(())));
 
         executor.send_request_read_response(
diff --git a/src/protocol/notification/negotiation.rs b/src/protocol/notification/negotiation.rs
index 8d238dfe..9c53c760 100644
--- a/src/protocol/notification/negotiation.rs
+++ b/src/protocol/notification/negotiation.rs
@@ -328,7 +328,6 @@ mod tests {
     use crate::{
         mock::substream::{DummySubstream, MockSubstream},
         types::SubstreamId,
-        Error,
     };
     use futures::StreamExt;
 
@@ -344,7 +343,10 @@ mod tests {
 
         let mut substream = MockSubstream::new();
         substream.expect_poll_ready().times(1).return_once(|_| Poll::Ready(Ok(())));
-        substream.expect_start_send().times(1).return_once(|_| Err(Error::Unknown));
+        substream
+            .expect_start_send()
+            .times(1)
+            .return_once(|_| Err(crate::error::SubstreamError::ConnectionClosed));
 
         let peer = PeerId::random();
         let substream = Substream::new_mock(peer, SubstreamId::from(0usize), Box::new(substream));
@@ -382,7 +384,7 @@ mod tests {
         substream
             .expect_poll_flush()
             .times(1)
-            .return_once(|_| Poll::Ready(Err(Error::Unknown)));
+            .return_once(|_| Poll::Ready(Err(crate::error::SubstreamError::ConnectionClosed)));
 
         let peer = PeerId::random();
         let substream = Substream::new_mock(peer, SubstreamId::from(0usize), Box::new(substream));
diff --git a/src/protocol/notification/tests/notification.rs b/src/protocol/notification/tests/notification.rs
index f766fc44..fc2c1ee7 100644
--- a/src/protocol/notification/tests/notification.rs
+++ b/src/protocol/notification/tests/notification.rs
@@ -19,7 +19,6 @@
 // DEALINGS IN THE SOFTWARE.
 
 use crate::{
-    error::Error,
     mock::substream::{DummySubstream, MockSubstream},
     protocol::{
         self,
@@ -1029,7 +1028,7 @@ async fn second_inbound_substream_opened_while_outbound_substream_was_opening()
     substream1
         .expect_poll_ready()
         .times(1)
-        .return_once(|_| Poll::Ready(Err(Error::Unknown)));
+        .return_once(|_| Poll::Ready(Err(SubstreamError::ConnectionClosed)));
 
     notif.peers.insert(
         peer,
diff --git a/src/protocol/notification/tests/substream_validation.rs b/src/protocol/notification/tests/substream_validation.rs
index cf2d6bb8..b2ac5054 100644
--- a/src/protocol/notification/tests/substream_validation.rs
+++ b/src/protocol/notification/tests/substream_validation.rs
@@ -256,7 +256,7 @@ async fn accept_fails_due_to_closed_substream() {
     substream
         .expect_poll_ready()
         .times(1)
-        .return_once(|_| Poll::Ready(Err(Error::SubstreamError(SubstreamError::ConnectionClosed))));
+        .return_once(|_| Poll::Ready(Err(SubstreamError::ConnectionClosed)));
 
     let (proto_tx, _proto_rx) = channel(256);
     tx.send(InnerTransportEvent::ConnectionEstablished {
diff --git a/src/protocol/request_response/handle.rs b/src/protocol/request_response/handle.rs
index 3ffb8d7b..fc3e6b71 100644
--- a/src/protocol/request_response/handle.rs
+++ b/src/protocol/request_response/handle.rs
@@ -65,6 +65,14 @@ pub enum RequestResponseError {
     UnsupportedProtocol,
 }
 
+impl std::cmp::PartialEq for RequestResponseError {
+    fn eq(&self, other: &Self) -> bool {
+        // We are not interested in the error details of rejections
+        // for equality checks.
+        core::mem::discriminant(self) == core::mem::discriminant(other)
+    }
+}
+
 /// The reason why a request was rejected.
 #[derive(Debug)]
 pub enum RejectReason {
@@ -162,7 +170,7 @@ impl From<InnerRequestResponseEvent> for RequestResponseEvent {
 }
 
 /// Request-response events.
-#[derive(Debug)]
+#[derive(Debug, PartialEq)]
 pub enum RequestResponseEvent {
     /// Request received from remote
     RequestReceived {
diff --git a/src/protocol/request_response/mod.rs b/src/protocol/request_response/mod.rs
index fd2dd1f1..b717886f 100644
--- a/src/protocol/request_response/mod.rs
+++ b/src/protocol/request_response/mod.rs
@@ -34,7 +34,6 @@ use crate::{
 
 use bytes::BytesMut;
 use futures::{channel, future::BoxFuture, stream::FuturesUnordered, StreamExt};
-use handle::RejectReason;
 use tokio::{
     sync::{
         mpsc::{Receiver, Sender},
@@ -54,7 +53,9 @@ use std::{
 };
 
 pub use config::{Config, ConfigBuilder};
-pub use handle::{DialOptions, RequestResponseError, RequestResponseEvent, RequestResponseHandle};
+pub use handle::{
+    DialOptions, RejectReason, RequestResponseError, RequestResponseEvent, RequestResponseHandle,
+};
 
 mod config;
 mod handle;
diff --git a/src/protocol/request_response/tests.rs b/src/protocol/request_response/tests.rs
index 9c75fcbe..73d8ce86 100644
--- a/src/protocol/request_response/tests.rs
+++ b/src/protocol/request_response/tests.rs
@@ -189,7 +189,7 @@ async fn inbound_substream_error() {
     substream
         .expect_poll_next()
         .times(1)
-        .return_once(|_| Poll::Ready(Some(Err(SubstreamError::Unknown))));
+        .return_once(|_| Poll::Ready(Some(Err(SubstreamError::ConnectionClosed))));
 
     // register inbound substream from peer
     protocol
diff --git a/src/transport/manager/handle.rs b/src/transport/manager/handle.rs
index f0b42904..0183832b 100644
--- a/src/transport/manager/handle.rs
+++ b/src/transport/manager/handle.rs
@@ -573,7 +573,7 @@ mod tests {
         handle.supported_transport.insert(SupportedTransport::Tcp);
 
         let err = handle.dial(&handle.local_peer_id).unwrap_err();
-        assert!(matches!(err, ImmediateDialError::NoAddressAvailable));
+        assert_eq!(err, ImmediateDialError::TriedToDialSelf);
 
         assert!(rx.try_recv().is_err());
     }
diff --git a/tests/protocol/request_response.rs b/tests/protocol/request_response.rs
index d34e85c2..ee962b87 100644
--- a/tests/protocol/request_response.rs
+++ b/tests/protocol/request_response.rs
@@ -22,8 +22,8 @@ use litep2p::{
     config::ConfigBuilder as Litep2pConfigBuilder,
     crypto::ed25519::Keypair,
     protocol::request_response::{
-        Config as RequestResponseConfig, ConfigBuilder, DialOptions, RequestResponseError,
-        RequestResponseEvent,
+        Config as RequestResponseConfig, ConfigBuilder, DialOptions, RejectReason,
+        RequestResponseError, RequestResponseEvent,
     },
     transport::tcp::config::Config as TcpConfig,
     types::{protocol::ProtocolName, RequestId},
@@ -314,7 +314,7 @@ async fn reject_request(transport1: Transport, transport2: Transport) {
         RequestResponseEvent::RequestFailed {
             peer: peer2,
             request_id,
-            error: RequestResponseError::Rejected
+            error: RequestResponseError::Rejected(RejectReason::ConnectionClosed)
         }
     );
 }
@@ -789,7 +789,7 @@ async fn connection_close_while_request_is_pending(transport1: Transport, transp
         RequestResponseEvent::RequestFailed {
             peer: peer2,
             request_id,
-            error: RequestResponseError::Rejected,
+            error: RequestResponseError::Rejected(RejectReason::ConnectionClosed),
         }
     );
 }
@@ -1005,7 +1005,7 @@ async fn response_too_big(transport1: Transport, transport2: Transport) {
         RequestResponseEvent::RequestFailed {
             peer: peer2,
             request_id,
-            error: RequestResponseError::Rejected,
+            error: RequestResponseError::Rejected(RejectReason::ConnectionClosed),
         }
     );
 }
@@ -1569,7 +1569,7 @@ async fn dial_peer_but_no_known_address(transport1: Transport, transport2: Trans
         RequestResponseEvent::RequestFailed {
             peer: peer2,
             request_id,
-            error: RequestResponseError::Rejected,
+            error: RequestResponseError::Rejected(RejectReason::ConnectionClosed),
         }
     );
 }
@@ -1916,7 +1916,7 @@ async fn excess_inbound_request_rejected(transport1: Transport, transport2: Tran
         RequestResponseEvent::RequestFailed {
             peer: peer2,
             request_id,
-            error: RequestResponseError::Rejected
+            error: RequestResponseError::Rejected(RejectReason::ConnectionClosed)
         }
     );
 }
@@ -2008,7 +2008,7 @@ async fn feedback_received_for_succesful_response(transport1: Transport, transpo
         .await
         .unwrap();
 
-    assert!(matches!(
+    assert_eq!(
         handle2.next().await.unwrap(),
         RequestResponseEvent::RequestReceived {
             peer: peer1,
@@ -2016,13 +2016,13 @@ async fn feedback_received_for_succesful_response(transport1: Transport, transpo
             request_id,
             request: vec![1, 3, 3, 7]
         },
-    ));
+    );
 
     // send response with feedback and verify that the response was sent successfully
     let (feedback_tx, feedback_rx) = channel::oneshot::channel();
     handle2.send_response_with_feedback(request_id, vec![1, 3, 3, 8], feedback_tx);
 
-    assert!(matches!(
+    assert_eq!(
         handle1.next().await.unwrap(),
         RequestResponseEvent::ResponseReceived {
             peer: peer2,
@@ -2030,7 +2030,7 @@ async fn feedback_received_for_succesful_response(transport1: Transport, transpo
             response: vec![1, 3, 3, 8],
             fallback: None,
         }
-    ));
+    );
     assert!(feedback_rx.await.is_ok());
 }
 
@@ -2350,7 +2350,7 @@ async fn dial_failure(transport: Transport) {
         RequestResponseEvent::RequestFailed {
             peer,
             request_id,
-            error: RequestResponseError::Rejected
+            error: RequestResponseError::Rejected(RejectReason::ConnectionClosed)
         }
     );
 }
@@ -2865,23 +2865,19 @@ async fn binary_incompatible_fallback_two_fallback_protocols_inbound_request(
         .await
         .unwrap();
 
-    match handle1.next().await.unwrap() {
+    assert_eq!(
+        handle1.next().await.unwrap(),
         RequestResponseEvent::RequestReceived {
             peer: peer2,
             fallback: Some(ProtocolName::from("/genesis/protocol/1")),
             request_id,
-            request,
-        } => {
-            assert_eq!(peer2, peer1);
-            assert_eq!(request_id, request_id);
-            assert_eq!(request, vec![1, 2, 3, 4]);
+            request: vec![1, 2, 3, 4],
         }
-        _ => panic!("unexpected event"),
-    };
+    );
 
     handle1.send_response(request_id, vec![1, 3, 3, 7]);
 
-    assert!(matches!(
+    assert_eq!(
         handle2.next().await.unwrap(),
         RequestResponseEvent::ResponseReceived {
             peer: peer1,
@@ -2889,7 +2885,7 @@ async fn binary_incompatible_fallback_two_fallback_protocols_inbound_request(
             response: vec![1, 3, 3, 7],
             fallback: None,
         }
-    ));
+    );
 }
 
 #[tokio::test]
@@ -2987,7 +2983,7 @@ async fn binary_incompatible_fallback_compatible_nodes(
         .await
         .unwrap();
 
-    assert!(matches!(
+    assert_eq!(
         handle2.next().await.unwrap(),
         RequestResponseEvent::RequestReceived {
             peer: peer1,
@@ -2995,11 +2991,11 @@ async fn binary_incompatible_fallback_compatible_nodes(
             request_id,
             request: vec![1, 2, 3, 4],
         }
-    ));
+    );
 
     handle2.send_response(request_id, vec![1, 3, 3, 7]);
 
-    assert!(matches!(
+    assert_eq!(
         handle1.next().await.unwrap(),
         RequestResponseEvent::ResponseReceived {
             peer: peer2,
@@ -3007,5 +3003,5 @@ async fn binary_incompatible_fallback_compatible_nodes(
             response: vec![1, 3, 3, 7],
             fallback: None,
         }
-    ));
+    );
 }
diff --git a/tests/substream.rs b/tests/substream.rs
index 1dde6d3b..dbce163b 100644
--- a/tests/substream.rs
+++ b/tests/substream.rs
@@ -21,6 +21,7 @@
 use litep2p::{
     codec::ProtocolCodec,
     config::ConfigBuilder,
+    error::SubstreamError,
     protocol::{Direction, TransportEvent, TransportService, UserProtocol},
     substream::{Substream, SubstreamSet},
     transport::tcp::config::Config as TcpConfig,
@@ -169,7 +170,7 @@ impl UserProtocol for CustomProtocol {
                             }
                             Some(mut substream) => {
                                 let payload = Bytes::from(payload);
-                                let res = substream.send(payload).await;
+                                let res = substream.send(payload).await.map_err(Into::into);
                                 tx.send(res).unwrap();
                                 let _ = substream.close().await;
                             }
@@ -411,12 +412,15 @@ async fn too_big_identity_payload_sink(transport1: Transport, transport2: Transp
             panic!("failed to open substream");
         };
 
-        // send too large paylod to peer
+        // send too large payload to peer
         let (tx, rx) = oneshot::channel();
         tx1.send(Command::SendPayloadSink(peer2, vec![0u8; 16], tx)).await.unwrap();
 
         match rx.await {
             Ok(Err(Error::IoError(ErrorKind::PermissionDenied))) => {}
+            Ok(Err(Error::SubstreamError(SubstreamError::IoError(
+                ErrorKind::PermissionDenied,
+            )))) => {}
             event => panic!("invalid event received: {event:?}"),
         }
     }