expand test_sniffer_intercept to make test comprehensive..

we need 2 sniffers to assert the message was correctly replaced and fully delivered over the TCP connection

roles/tests-integration/tests/sniffer_integration.rs

@@ -7,10 +7,15 @@ use roles_logic_sv2::{
 use sniffer::{InterceptMessage, MessageDirection};
 use std::convert::TryInto;
 
+// this test aims to assert that Sniffer is able to intercept and replace some message
+// sniffer_a replaces a SetupConnectionSuccess from TP with a SetupConnectionError directed at Pool
+// sniffer_b asserts that Pool is about to receive a SetupConnectionError
+// TP -> sniffer_a -> sniffer_b -> Pool
 #[tokio::test]
 async fn test_sniffer_intercept() {
-    let (_tp, tp_addr) = start_template_provider(None).await;
     use const_sv2::MESSAGE_TYPE_SETUP_CONNECTION_SUCCESS;
+
+    let (_tp, tp_addr) = start_template_provider(None).await;
     let message_replacement =
         PoolMessages::Common(CommonMessages::SetupConnectionError(SetupConnectionError {
             flags: 0,
@@ -26,9 +31,21 @@ async fn test_sniffer_intercept() {
         message_replacement,
         MESSAGE_TYPE_SETUP_CONNECTION_ERROR,
     );
-    let (sniffer, sniffer_addr) =
-        start_sniffer("".to_string(), tp_addr, false, Some(vec![intercept])).await;
-    let _ = start_pool(Some(sniffer_addr)).await;
-    assert_common_message!(&sniffer.next_message_from_downstream(), SetupConnection);
-    assert_common_message!(&sniffer.next_message_from_upstream(), SetupConnectionError);
+
+    // this sniffer will replace SetupConnectionSuccess with SetupConnectionError
+    let (_sniffer_a, sniffer_a_addr) =
+        start_sniffer("A".to_string(), tp_addr, false, Some(vec![intercept])).await;
+
+    // this sniffer will assert SetupConnectionSuccess was correctly replaced with
+    // SetupConnectionError
+    let (sniffer_b, sniffer_b_addr) =
+        start_sniffer("B".to_string(), sniffer_a_addr, false, None).await;
+
+    let _ = start_pool(Some(sniffer_b_addr)).await;
+
+    // assert sniffer_a functionality of replacing messages work as expected (goal of this test)
+    assert_common_message!(
+        &sniffer_b.next_message_from_upstream(),
+        SetupConnectionError
+    );
 }