don't use fundgroup for single funder in crossrefxml writer

Author: mfenner

cmd/root.go

@@ -13,7 +13,7 @@ import (
 // rootCmd represents the base command when called without any subcommands
 var rootCmd = &cobra.Command{
 	Use:     "commonmeta",
-	Version: "v0.13.4",
+	Version: "v0.13.5",
 	Short:   "Convert scholarly metadata between formats",
 	Long: `Convert scholarly metadata between formats. Currently
 supported formats include Crossref, DataCite, Schema.org, CSL, InvenioRDM,

crossrefxml/writer.go

@@ -259,11 +259,15 @@ func Convert(data commonmeta.Data) (Body, error) {
 				}
 				a = append(a, f)
 			}
-			fg := Assertion{
-				Name:      "fundgroup",
-				Assertion: a,
+			if len(data.FundingReferences) > 1 {
+				fg := Assertion{
+					Name:      "fundgroup",
+					Assertion: a,
+				}
+				assertion = append(assertion, fg)
+			} else {
+				assertion = append(assertion, a...)
 			}
-			assertion = append(assertion, fg)
 		}
 		program = append(program, Program{
 			Name:      "fundref",