fix: utf8 decoding and add test to prevent it

proto/src/message/primitive/pgstring.rs

@@ -41,15 +41,33 @@ impl Encode for PgString {
 
 impl Decode for PgString {
     fn decode<D: Decoder>(decoder: &mut D) -> Result<Self, DecodeError> {
-        let mut string = String::new();
+        let mut bytes = Vec::new();
         loop {
             let byte = u8::decode(decoder)?;
             if byte == 0 {
                 break;
             }
-            string.push(byte as char);
+            bytes.push(byte);
         }
 
+        let string = String::from_utf8(bytes)
+            .map_err(|e| DecodeError::Utf8 { inner: e.utf8_error() })?;
         Ok(PgString(string))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::message::primitive::data::MessageData;
+    use super::*;
+
+    #[test]
+    fn test_encode_decode_utf8() {
+        let pg_string = PgString::from("áhój jěžkó");
+        let encoded = pg_string.serialize().unwrap();
+        let decoded: PgString = PgString::deserialize(&encoded).unwrap();
+
+        let actual = decoded.as_str();
+        assert_eq!("áhój jěžkó", actual);
+    }
+}