Refactor connection handler unit tests to adapt with new API

.changelog/unreleased/improvements/440-refactor-conn-unit-tests.md

@@ -0,0 +1,2 @@
+- Refactor connection handler unit tests to adapt with new Validation/Execution API
+([#440](https://github.com/cosmos/ibc-rs/issues/440)).

crates/ibc/src/core/handler.rs

@@ -50,10 +50,8 @@ mod tests {
         ConnectionEnd, Counterparty as ConnCounterparty, State as ConnState,
     };
     use crate::core::ics03_connection::msgs::{
-        conn_open_ack::{test_util::get_dummy_raw_msg_conn_open_ack, MsgConnectionOpenAck},
-        conn_open_init::{test_util::get_dummy_raw_msg_conn_open_init, MsgConnectionOpenInit},
-        conn_open_try::{test_util::get_dummy_raw_msg_conn_open_try, MsgConnectionOpenTry},
-        ConnectionMsg,
+        conn_open_ack::MsgConnectionOpenAck, conn_open_init::MsgConnectionOpenInit,
+        conn_open_try::MsgConnectionOpenTry, ConnectionMsg,
     };
     use crate::core::ics03_connection::version::Version as ConnVersion;
     use crate::core::ics04_channel::channel::ChannelEnd;
@@ -162,26 +160,15 @@ mod tests {
         //
         // Connection handshake messages.
         //
-        let msg_conn_init =
-            MsgConnectionOpenInit::try_from(get_dummy_raw_msg_conn_open_init(None)).unwrap();
+        let msg_conn_init = MsgConnectionOpenInit::new_dummy();
 
-        let correct_msg_conn_try = MsgConnectionOpenTry::try_from(get_dummy_raw_msg_conn_open_try(
-            client_height,
-            client_height,
-        ))
-        .unwrap();
+        let correct_msg_conn_try = MsgConnectionOpenTry::new_dummy(client_height, client_height);
 
         // The handler will fail to process this msg because the client height is too advanced.
-        let incorrect_msg_conn_try = MsgConnectionOpenTry::try_from(
-            get_dummy_raw_msg_conn_open_try(client_height + 1, client_height + 1),
-        )
-        .unwrap();
+        let incorrect_msg_conn_try =
+            MsgConnectionOpenTry::new_dummy(client_height + 1, client_height + 1);
 
-        let msg_conn_ack = MsgConnectionOpenAck::try_from(get_dummy_raw_msg_conn_open_ack(
-            client_height,
-            client_height,
-        ))
-        .unwrap();
+        let msg_conn_ack = MsgConnectionOpenAck::new_dummy(client_height, client_height);
 
         //
         // Channel handshake messages.

crates/ibc/src/core/ics03_connection/handler.rs

@@ -54,3 +54,40 @@ where
         ConnectionMsg::OpenConfirm(msg) => conn_open_confirm::process(ctx, msg),
     }
 }
+
+#[cfg(test)]
+pub mod test_util {
+    use core::fmt::Debug;
+
+    use crate::{core::ContextError, mock::context::MockContext, prelude::String};
+    use alloc::format;
+
+    pub enum Expect {
+        Success,
+        Failure(Option<ContextError>),
+    }
+
+    #[derive(Clone, Debug)]
+    pub struct Fixture<M: Debug> {
+        pub ctx: MockContext,
+        pub msg: M,
+    }
+
+    impl<M: Debug> Fixture<M> {
+        pub fn generate_error_msg(
+            &self,
+            expect: &Expect,
+            process: &str,
+            res: &Result<(), ContextError>,
+        ) -> String {
+            let base_error = match expect {
+                Expect::Success => "step failed!",
+                Expect::Failure(_) => "step passed but was supposed to fail!",
+            };
+            format!(
+                "{process} {base_error} /n {res:?} /n {:?} /n {:?}",
+                &self.msg, &self.ctx
+            )
+        }
+    }
+}