Compare the additional properties on headlines.

src/compare/diff.rs

@@ -21,6 +21,7 @@ use super::elisp_fact::GetElispFact;
 use super::sexp::unquote;
 use super::sexp::Token;
 use super::util::assert_no_children;
+use super::util::compare_additional_properties;
 use super::util::compare_children;
 use super::util::compare_children_iter;
 use super::util::compare_standard_properties;
@@ -537,12 +538,27 @@ fn compare_heading<'b, 's>(
     let mut child_status = Vec::new();
     let mut message = None;
 
-    // TODO: Add checks to compare values for additional properties.
     let additional_property_names: Vec<String> = rust
         .get_additional_properties()
         .map(|node_property| format!(":{}", node_property.property_name.to_uppercase()))
         .collect();
 
+    let additional_properties: Vec<(String, &str)> = rust
+        .get_additional_properties()
+        .map(|node_property| {
+            (
+                format!(":{}", node_property.property_name.to_uppercase()),
+                node_property.value.unwrap_or(""),
+            )
+        })
+        .collect();
+
+    compare_additional_properties(emacs, additional_properties.into_iter())?.apply(
+        &mut child_status,
+        &mut this_status,
+        &mut message,
+    );
+
     compare_children(
         source,
         emacs,