test(protocol,core,bridge): add 83 unit tests for untested modules (TODO-015,018,019,021)

Protocol DTO: 32 serde roundtrip + edge case tests.
Core events: 27 event construction + variant coverage tests.
Bridge: 24 error mapping + DTO roundtrip tests.
Add serde_json dev-dependency to protocol and bridge crates.

crates/chanora_bridge/src/lib.rs

@@ -51,7 +51,7 @@ use thiserror::Error;
 /// Errors raised at the bridge boundary. Production code must keep
 /// these user-safe — no secrets, no protocol details, no path
 /// information beyond what the redaction policy permits.
-#[derive(Debug, Error, Clone, serde::Serialize, serde::Deserialize)]
+#[derive(Debug, Error, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
 pub enum BridgeError {
     /// The caller submitted a malformed command DTO.
     #[error("invalid command: {0}")]
@@ -125,3 +125,308 @@ impl From<chanora_core::CoreError> for BridgeError {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn roundtrip_json<
+        T: serde::Serialize + serde::de::DeserializeOwned + PartialEq + std::fmt::Debug,
+    >(
+        value: &T,
+    ) {
+        let json = serde_json::to_string(value).expect("serialize");
+        let back: T = serde_json::from_str(&json).expect("deserialize");
+        assert_eq!(&back, value, "roundtrip failed");
+    }
+
+    #[test]
+    fn bridge_error_invalid_command() {
+        let err = BridgeError::InvalidCommand("bad".to_string());
+        assert_eq!(err.to_string(), "invalid command: bad");
+    }
+
+    #[test]
+    fn bridge_error_dns_failed() {
+        let err = BridgeError::DnsFailed {
+            host: "example.com".to_string(),
+            reason: "timeout".to_string(),
+        };
+        let msg = err.to_string();
+        assert!(msg.contains("example.com"));
+        assert!(msg.contains("timeout"));
+    }
+
+    #[test]
+    fn bridge_error_connection() {
+        let err = BridgeError::Connection("refused".to_string());
+        assert_eq!(err.to_string(), "connection: refused");
+    }
+
+    #[test]
+    fn bridge_error_not_connected() {
+        let err = BridgeError::NotConnected;
+        assert_eq!(err.to_string(), "not connected");
+    }
+
+    #[test]
+    fn bridge_error_already_connected() {
+        let err = BridgeError::AlreadyConnected;
+        assert_eq!(err.to_string(), "already connected");
+    }
+
+    #[test]
+    fn bridge_error_server_rejected() {
+        let err = BridgeError::ServerRejected {
+            code: 2568,
+            message: "insufficient permissions".to_string(),
+        };
+        let msg = err.to_string();
+        assert!(msg.contains("2568"));
+        assert!(msg.contains("insufficient permissions"));
+    }
+
+    #[test]
+    fn bridge_error_unmapped() {
+        let err = BridgeError::Unmapped("mystery".to_string());
+        assert_eq!(err.to_string(), "unmapped: mystery");
+    }
+
+    #[test]
+    fn bridge_error_serde_roundtrip() {
+        roundtrip_json(&BridgeError::InvalidCommand("test".to_string()));
+        roundtrip_json(&BridgeError::NotConnected);
+        roundtrip_json(&BridgeError::AlreadyConnected);
+        roundtrip_json(&BridgeError::Connection("fail".to_string()));
+        roundtrip_json(&BridgeError::Unmapped("x".to_string()));
+        roundtrip_json(&BridgeError::DnsFailed {
+            host: "h".to_string(),
+            reason: "r".to_string(),
+        });
+        roundtrip_json(&BridgeError::ServerRejected {
+            code: 42,
+            message: "nope".to_string(),
+        });
+    }
+
+    #[test]
+    fn bridge_error_clone_preserves() {
+        let err = BridgeError::InvalidCommand("orig".to_string());
+        let cloned = err.clone();
+        assert_eq!(cloned.to_string(), err.to_string());
+    }
+
+    #[test]
+    fn from_core_error_not_connected() {
+        let core_err = chanora_core::CoreError::NotConnected;
+        let bridge_err: BridgeError = core_err.into();
+        assert!(matches!(bridge_err, BridgeError::NotConnected));
+    }
+
+    #[test]
+    fn from_core_error_already_connected() {
+        let core_err = chanora_core::CoreError::AlreadyConnected;
+        let bridge_err: BridgeError = core_err.into();
+        assert!(matches!(bridge_err, BridgeError::AlreadyConnected));
+    }
+
+    #[test]
+    fn from_core_error_audio_not_started() {
+        let core_err = chanora_core::CoreError::AudioNotStarted;
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::InvalidCommand(msg) => {
+                assert!(msg.contains("audio not started"));
+            }
+            other => panic!("expected InvalidCommand, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_dns_failed() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::DnsFailed {
+                host: "bad.host".to_string(),
+                reason: "no address".to_string(),
+            },
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::DnsFailed { host, reason } => {
+                assert_eq!(host, "bad.host");
+                assert_eq!(reason, "no address");
+            }
+            other => panic!("expected DnsFailed, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_server_rejected() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::ServerRejected {
+                code: 0x0501,
+                message: "channel password wrong".to_string(),
+            },
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::ServerRejected { code, message } => {
+                assert_eq!(code, 0x0501);
+                assert_eq!(message, "channel password wrong");
+            }
+            other => panic!("expected ServerRejected, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_file_transfer() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::FileTransfer("disk full".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("file transfer"));
+                assert!(msg.contains("disk full"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_generic() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::Connect("refused".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("refused"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_lost() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::Lost("timeout".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("timeout"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_invalid() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::Invalid("bad config".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("bad config"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_disconnected_early() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::DisconnectedEarly("premature".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("premature"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_identity() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::Identity("parse error".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("parse error"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_timeout() {
+        let core_err =
+            chanora_core::CoreError::Protocol(chanora_core::ProtocolError::Timeout);
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("timeout"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_protocol_backend() {
+        let core_err = chanora_core::CoreError::Protocol(
+            chanora_core::ProtocolError::Backend("raw".to_string()),
+        );
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Connection(msg) => {
+                assert!(msg.contains("raw"));
+            }
+            other => panic!("expected Connection, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn from_core_error_invariant() {
+        let core_err = chanora_core::CoreError::Invariant("broken");
+        let bridge_err: BridgeError = core_err.into();
+        match bridge_err {
+            BridgeError::Unmapped(msg) => {
+                assert!(msg.contains("broken"));
+            }
+            other => panic!("expected Unmapped, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn error_surfaces_all_protocol_error_variants() {
+        let protocol_errors: Vec<chanora_core::ProtocolError> = vec![
+            chanora_core::ProtocolError::Invalid("x".into()),
+            chanora_core::ProtocolError::DnsFailed {
+                host: "h".into(),
+                reason: "r".into(),
+            },
+            chanora_core::ProtocolError::Connect("c".into()),
+            chanora_core::ProtocolError::DisconnectedEarly("d".into()),
+            chanora_core::ProtocolError::Lost("l".into()),
+            chanora_core::ProtocolError::Identity("i".into()),
+            chanora_core::ProtocolError::Timeout,
+            chanora_core::ProtocolError::ServerRejected {
+                code: 1,
+                message: "m".into(),
+            },
+            chanora_core::ProtocolError::Backend("b".into()),
+            chanora_core::ProtocolError::FileTransfer("f".into()),
+        ];
+        for p_err in protocol_errors {
+            let core_err = chanora_core::CoreError::Protocol(p_err);
+            let bridge_err: BridgeError = core_err.into();
+            let msg = bridge_err.to_string();
+            assert!(!msg.is_empty(), "BridgeError message must not be empty");
+        }
+    }
+}