xso: reject duplicate children

This was an oversight. Even though we apparently don't have tests for
this anywhere, it is what the old functional macros do.

parsers/src/forwarding.rs

@@ -96,4 +96,36 @@ mod tests {
         let serialized: Element = forwarded.into();
         assert_eq!(serialized, reference);
     }
+
+    #[test]
+    fn test_invalid_duplicate_delay() {
+        let elem: Element = "<forwarded xmlns='urn:xmpp:forward:0'><delay xmlns='urn:xmpp:delay' from='capulet.com' stamp='2002-09-10T23:08:25+00:00'/><delay xmlns='urn:xmpp:delay' from='capulet.com' stamp='2002-09-10T23:08:25+00:00'/><message xmlns='jabber:client' to='juliet@capulet.example/balcony' from='romeo@montague.example/home'/></forwarded>"
+            .parse()
+            .unwrap();
+        let error = Forwarded::try_from(elem).unwrap_err();
+        let message = match error {
+            FromElementError::Invalid(Error::Other(string)) => string,
+            _ => panic!(),
+        };
+        assert_eq!(
+            message,
+            "Element forwarded must not have more than one delay child."
+        );
+    }
+
+    #[test]
+    fn test_invalid_duplicate_message() {
+        let elem: Element = "<forwarded xmlns='urn:xmpp:forward:0'><delay xmlns='urn:xmpp:delay' from='capulet.com' stamp='2002-09-10T23:08:25+00:00'/><message xmlns='jabber:client' to='juliet@capulet.example/balcony' from='romeo@montague.example/home'/><message xmlns='jabber:client' to='juliet@capulet.example/balcony' from='romeo@montague.example/home'/></forwarded>"
+            .parse()
+            .unwrap();
+        let error = Forwarded::try_from(elem).unwrap_err();
+        let message = match error {
+            FromElementError::Invalid(Error::Other(string)) => string,
+            _ => panic!(),
+        };
+        assert_eq!(
+            message,
+            "Element forwarded must not have more than one message child."
+        );
+    }
 }

parsers/src/private.rs

@@ -39,3 +39,26 @@ pub struct Query {
 impl IqSetPayload for Query {}
 impl IqGetPayload for Query {}
 impl IqResultPayload for Query {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use minidom::Element;
+    use xso::error::{Error, FromElementError};
+
+    #[test]
+    fn test_invalid_duplicate_child() {
+        let elem: Element = "<query xmlns='jabber:iq:private'><storage xmlns='storage:bookmarks'/><storage xmlns='storage:bookmarks'/></query>"
+            .parse()
+            .unwrap();
+        let error = Query::try_from(elem).unwrap_err();
+        let message = match error {
+            FromElementError::Invalid(Error::Other(string)) => string,
+            _ => panic!(),
+        };
+        assert_eq!(
+            message,
+            "Query element must not have more than one child in field 'storage'."
+        );
+    }
+}

parsers/src/util/macro_tests.rs

@@ -522,6 +522,19 @@ fn parent_positive() {
     assert_eq!(v.child.foo, "hello world!");
 }
 
+#[test]
+fn parent_negative_duplicate_child() {
+    #[allow(unused_imports)]
+    use std::{
+        option::Option::{None, Some},
+        result::Result::{Err, Ok},
+    };
+    match parse_str::<Parent>("<parent xmlns='urn:example:ns1'><attr foo='hello world!'/><attr foo='hello world!'/></parent>") {
+        Err(::xso::error::FromElementError::Invalid(::xso::error::Error::Other(e))) if e.contains("must not have more than one") => (),
+        other => panic!("unexpected result: {:?}", other),
+    }
+}
+
 #[derive(FromXml, AsXml, PartialEq, Debug, Clone)]
 #[xml(namespace = NS1, name = "parent")]
 struct OptionalChild {