You can now add document references that are part of a document information

src/ifcopenshell-python/ifcopenshell/api/document/add_reference.py

@@ -16,16 +16,17 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
 
-import ifcopenshell
-
 
 class Usecase:
     def __init__(self, file, **settings):
         self.file = file
-        self.settings = {}
+        self.settings = {"information": None}
         for key, value in settings.items():
             self.settings[key] = value
 
     def execute(self):
         id_attribute = "ItemReference" if self.file.schema == "IFC2X3" else "Identification"
-        return self.file.create_entity("IfcDocumentReference", **{id_attribute: ifcopenshell.guid.new()})
+        attributes = {id_attribute: "X"}
+        if self.file.schema != "IFC2X3":
+            attributes["ReferencedDocument"] = self.settings["information"]
+        return self.file.create_entity("IfcDocumentReference", **attributes)

src/ifcopenshell-python/test/api/document/test_add_reference_.py

@@ -0,0 +1,35 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2022 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import test.bootstrap
+import ifcopenshell.api
+
+
+class TestAddReference(test.bootstrap.IFC4):
+    def test_adding_a_reference(self):
+        element = ifcopenshell.api.run("document.add_reference", self.file, information=None)
+        assert element.is_a("IfcDocumentReference")
+        assert len(self.file.by_type("IfcDocumentReference")) == 1
+
+    def test_adding_a_reference_to_an_information(self):
+        self.file.createIfcProject()
+        information = ifcopenshell.api.run("document.add_information", self.file, parent=None)
+        element = ifcopenshell.api.run("document.add_reference", self.file, information=information)
+        assert element.is_a("IfcDocumentReference")
+        assert len(self.file.by_type("IfcDocumentReference")) == 1
+        assert element.ReferencedDocument == information