diff --git a/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py b/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py
index 38ae9408e6..0029ac94a0 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/classification/remove_classification.py
@@ -58,15 +58,20 @@ class Usecase:
                 self.file.remove(rel)
                 if history:
                     ifcopenshell.util.element.remove_deep2(self.file, history)
-        for rel in self.file.by_type("IfcExternalReferenceRelationship"):
-            if not rel.RelatingReference:
-                self.file.remove(rel)
 
-    def get_references(self, classification):
+        if self.file.schema != "IFC2X3":
+            for rel in self.file.by_type("IfcExternalReferenceRelationship"):
+                if not rel.RelatingReference:
+                    self.file.remove(rel)
+
+    def get_references(self, classification: ifcopenshell.entity_instance) -> list[ifcopenshell.entity_instance]:
         results = []
-        if not classification.HasReferences:
-            return results
-        for reference in classification.HasReferences:
-            results.append(reference)
-            results.extend(self.get_references(reference))
+        if self.file.schema == "IFC2X3":
+            for reference in self.file.by_type("IfcClassificationReference"):
+                if reference.ReferencedSource == classification:
+                    results.append(reference)
+        else:
+            for reference in classification.HasReferences:
+                results.append(reference)
+                results.extend(self.get_references(reference))
         return results
diff --git a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py
index 95c638182a..65c95ca0d1 100644
--- a/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py
+++ b/src/ifcopenshell-python/ifcopenshell/api/cost/add_cost_schedule.py
@@ -62,5 +62,17 @@ def add_cost_schedule(file: ifcopenshell.file, name: Optional[str] = None, prede
         predefined_type=settings["predefined_type"],
         name=settings["name"],
     )
-    cost_schedule.UpdateDate = ifcopenshell.util.date.datetime2ifc(datetime.now(), "IfcDateTime")
+    if file.schema == "IFC2X3":
+        cost_schedule.UpdateDate = createIfcDateAndTime(file, datetime.now())
+    else:
+        cost_schedule.UpdateDate = ifcopenshell.util.date.datetime2ifc(datetime.now(), "IfcDateTime")
     return cost_schedule
+
+
+def createIfcDateAndTime(file: ifcopenshell.file, dt: datetime):
+    ifc_dt = file.create_entity("IfcDateAndTime")
+    ifc_dt.DateComponent = file.create_entity(
+        "IfcCalendarDate", **ifcopenshell.util.date.datetime2ifc(dt, "IfcCalendarDate")
+    )
+    ifc_dt.TimeComponent = file.create_entity("IfcLocalTime", **ifcopenshell.util.date.datetime2ifc(dt, "IfcLocalTime"))
+    return ifc_dt
diff --git a/src/ifcopenshell-python/test/api/aggregate/test_assign_object.py b/src/ifcopenshell-python/test/api/aggregate/test_assign_object.py
index c43733f426..e1036e16e3 100644
--- a/src/ifcopenshell-python/test/api/aggregate/test_assign_object.py
+++ b/src/ifcopenshell-python/test/api/aggregate/test_assign_object.py
@@ -121,3 +121,7 @@ class TestAssignObject(test.bootstrap.IFC4):
         ifcopenshell.api.run("spatial.assign_container", self.file, products=[subelement], relating_structure=container)
         ifcopenshell.api.run("aggregate.assign_object", self.file, products=[subelement], relating_object=element)
         assert not ifcopenshell.util.element.get_container(subelement, should_get_direct=True)
+
+
+class TestAssignObjectIFC2X3(test.bootstrap.IFC2X3, TestAssignObject):
+    pass
diff --git a/src/ifcopenshell-python/test/api/aggregate/test_unassign_object.py b/src/ifcopenshell-python/test/api/aggregate/test_unassign_object.py
index 64e4fe4fcd..8619275fd7 100644
--- a/src/ifcopenshell-python/test/api/aggregate/test_unassign_object.py
+++ b/src/ifcopenshell-python/test/api/aggregate/test_unassign_object.py
@@ -49,3 +49,7 @@ class TestUnassignObject(test.bootstrap.IFC4):
         ifcopenshell.api.run("aggregate.assign_object", self.file, products=[subelement], relating_object=element)
         ifcopenshell.api.run("aggregate.unassign_object", self.file, products=[subelement])
         assert len(self.file.by_type("IfcRelAggregates")) == 0
+
+
+class TestUnassignObjectIFC2X3(test.bootstrap.IFC2X3, TestUnassignObject):
+    pass
diff --git a/src/ifcopenshell-python/test/api/boundary/test_copy_boundary.py b/src/ifcopenshell-python/test/api/boundary/test_copy_boundary.py
index b044d32eac..e5a8b98437 100644
--- a/src/ifcopenshell-python/test/api/boundary/test_copy_boundary.py
+++ b/src/ifcopenshell-python/test/api/boundary/test_copy_boundary.py
@@ -34,3 +34,7 @@ class TestCopyBoundary(test.bootstrap.IFC4):
         boundary2 = ifcopenshell.api.run("boundary.copy_boundary", self.file, boundary=boundary)
         assert boundary2.ConnectionGeometry.is_a("IfcConnectionSurfaceGeometry")
         assert boundary2.ConnectionGeometry != boundary.ConnectionGeometry
+
+
+class TestCopyBoundaryIFC2X3(test.bootstrap.IFC2X3, TestCopyBoundary):
+    pass
diff --git a/src/ifcopenshell-python/test/api/boundary/test_remove_boundary.py b/src/ifcopenshell-python/test/api/boundary/test_remove_boundary.py
index 7a6f3a0a16..cd3b5ff54b 100644
--- a/src/ifcopenshell-python/test/api/boundary/test_remove_boundary.py
+++ b/src/ifcopenshell-python/test/api/boundary/test_remove_boundary.py
@@ -33,3 +33,7 @@ class TestRemoveBoundary(test.bootstrap.IFC4):
         ifcopenshell.api.run("boundary.remove_boundary", self.file, boundary=boundary)
         assert not self.file.by_type("IfcRelSpaceBoundary")
         assert not self.file.by_type("IfcConnectionSurfaceGeometry")
+
+
+class TestRemoveBoundaryIFC2X3(test.bootstrap.IFC2X3, TestRemoveBoundary):
+    pass
diff --git a/src/ifcopenshell-python/test/api/classification/test_add_classification.py b/src/ifcopenshell-python/test/api/classification/test_add_classification.py
index 2c80cfb52f..0255e1240c 100644
--- a/src/ifcopenshell-python/test/api/classification/test_add_classification.py
+++ b/src/ifcopenshell-python/test/api/classification/test_add_classification.py
@@ -32,3 +32,7 @@ class TestAddClassification(test.bootstrap.IFC4):
         ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcProject")
         ifcopenshell.api.run("classification.add_classification", self.file, classification=classification)
         assert self.file.by_type("IfcClassification")[0].Name == "Name"
+
+
+class TestAddClassificationIFC2X3(test.bootstrap.IFC2X3, TestAddClassification):
+    pass
diff --git a/src/ifcopenshell-python/test/api/classification/test_remove_classification.py b/src/ifcopenshell-python/test/api/classification/test_remove_classification.py
index fb3537ddf2..319384306e 100644
--- a/src/ifcopenshell-python/test/api/classification/test_remove_classification.py
+++ b/src/ifcopenshell-python/test/api/classification/test_remove_classification.py
@@ -47,7 +47,7 @@ class TestRemoveClassification(test.bootstrap.IFC4):
     def test_removing_a_classification_and_all_of_its_references_when_associated_with_a_resource(self):
         ifcopenshell.api.run("root.create_entity", self.file, ifc_class="IfcProject")
         result = ifcopenshell.api.run("classification.add_classification", self.file, classification="Name")
-        element = self.file.createIfcMaterial(Name="Material")
+        element = self.file.create_entity("IfcWall", Name="Wall")
         ifcopenshell.api.run(
             "classification.add_reference",
             self.file,
@@ -59,4 +59,9 @@ class TestRemoveClassification(test.bootstrap.IFC4):
         ifcopenshell.api.run("classification.remove_classification", self.file, classification=result)
         assert not self.file.by_type("IfcClassification")
         assert not self.file.by_type("IfcClassificationReference")
-        assert not self.file.by_type("IfcExternalReferenceRelationship")
+        if self.file.schema != "IFC2X3":
+            assert not self.file.by_type("IfcExternalReferenceRelationship")
+
+
+class TestRemoveClassificationIFC2X3(test.bootstrap.IFC2X3, TestRemoveClassification):
+    pass
diff --git a/src/ifcopenshell-python/test/api/context/test_add_context.py b/src/ifcopenshell-python/test/api/context/test_add_context.py
index c44ae9d0f9..2a427ef889 100644
--- a/src/ifcopenshell-python/test/api/context/test_add_context.py
+++ b/src/ifcopenshell-python/test/api/context/test_add_context.py
@@ -75,3 +75,7 @@ class TestAddContext(test.bootstrap.IFC4):
         self.test_adding_a_2d_context()
         project = self.file.by_type("IfcProject")[0]
         assert len(project.RepresentationContexts) == 2
+
+
+class TestAddContextIFC2X3(test.bootstrap.IFC2X3, TestAddContext):
+    pass
diff --git a/src/ifcopenshell-python/test/api/context/test_edit_context.py b/src/ifcopenshell-python/test/api/context/test_edit_context.py
index 1232496b95..210f667f7d 100644
--- a/src/ifcopenshell-python/test/api/context/test_edit_context.py
+++ b/src/ifcopenshell-python/test/api/context/test_edit_context.py
@@ -58,3 +58,7 @@ class TestEditContext(test.bootstrap.IFC4):
         assert subcontext.TargetScale == 0.5
         assert subcontext.TargetView == "MODEL_VIEW"
         assert subcontext.UserDefinedTargetView == "UserDefinedTargetView"
+
+
+class TestEditContext(test.bootstrap.IFC2X3, TestEditContext):
+    pass
diff --git a/src/ifcopenshell-python/test/api/context/test_remove_context.py b/src/ifcopenshell-python/test/api/context/test_remove_context.py
index f4948dcb4b..682990e154 100644
--- a/src/ifcopenshell-python/test/api/context/test_remove_context.py
+++ b/src/ifcopenshell-python/test/api/context/test_remove_context.py
@@ -38,16 +38,22 @@ class TestRemoveContext(test.bootstrap.IFC4):
         subcontext = self.file.createIfcGeometricRepresentationSubcontext()
         subcontext.ParentContext = context
         representation = self.file.createIfcRepresentation(ContextOfItems=subcontext)
-        projected_crs = self.file.createIfcProjectedCRS()
-        map_conversion = self.file.createIfcMapConversion(SourceCRS=subcontext, TargetCRS=projected_crs)
+        if self.file.schema != "IFC2X3":
+            projected_crs = self.file.createIfcProjectedCRS()
+            map_conversion = self.file.createIfcMapConversion(SourceCRS=subcontext, TargetCRS=projected_crs)
         ifcopenshell.api.run("context.remove_context", self.file, context=subcontext)
         assert len(self.file.by_type("IfcGeometricRepresentationSubcontext")) == 0
         assert representation in self.file.get_inverse(context)
-        assert len(self.file.by_type("IfcMapConversion")) == 0
-        assert len(self.file.by_type("IfcProjectedCRS")) == 0
+        if self.file.schema != "IFC2X3":
+            assert len(self.file.by_type("IfcMapConversion")) == 0
+            assert len(self.file.by_type("IfcProjectedCRS")) == 0
 
     def test_removing_a_context_with_references(self):
         context = self.file.createIfcGeometricRepresentationContext()
         representation = self.file.createIfcRepresentation(ContextOfItems=context)
         ifcopenshell.api.run("context.remove_context", self.file, context=context)
         assert len([e for e in self.file]) == 0
+
+
+class TestRemoveContextIFC2X3(test.bootstrap.IFC2X3, TestRemoveContext):
+    pass
diff --git a/src/ifcopenshell-python/test/api/control/test_assign_control.py b/src/ifcopenshell-python/test/api/control/test_assign_control.py
index 18670c86e4..e8d63d5d6f 100644
--- a/src/ifcopenshell-python/test/api/control/test_assign_control.py
+++ b/src/ifcopenshell-python/test/api/control/test_assign_control.py
@@ -48,3 +48,7 @@ class TestAssignControl(test.bootstrap.IFC4):
         assert len(self.file.by_type("IfcRelAssignsToControl")) == 1
         assert relation.RelatingControl == control
         assert set(relation.RelatedObjects) == set((wall, wall1))
+
+
+class TestAssignControlIFC2X3(test.bootstrap.IFC2X3, TestAssignControl):
+    pass
diff --git a/src/ifcopenshell-python/test/api/control/test_unassign_control.py b/src/ifcopenshell-python/test/api/control/test_unassign_control.py
index c31014f008..c85ee05765 100644
--- a/src/ifcopenshell-python/test/api/control/test_unassign_control.py
+++ b/src/ifcopenshell-python/test/api/control/test_unassign_control.py
@@ -41,3 +41,7 @@ class TestUnassignControl(test.bootstrap.IFC4):
         ifcopenshell.api.run("control.unassign_control", self.file, relating_control=control, related_object=wall1)
         assert len(self.file.by_type("IfcRelAssignsToControl")) == 1
         assert relation.RelatedObjects == (wall,)
+
+
+class TestUnassignControlIFC2X3(test.bootstrap.IFC2X3, TestUnassignControl):
+    pass
diff --git a/src/ifcopenshell-python/test/api/cost/test_add_cost_item.py b/src/ifcopenshell-python/test/api/cost/test_add_cost_item.py
index 488f10aadc..b2bec35bbf 100644
--- a/src/ifcopenshell-python/test/api/cost/test_add_cost_item.py
+++ b/src/ifcopenshell-python/test/api/cost/test_add_cost_item.py
@@ -18,6 +18,7 @@
 
 import test.bootstrap
 import ifcopenshell.api
+import ifcopenshell.util.element
 
 
 class TestAddCostItem(test.bootstrap.IFC4):
@@ -33,4 +34,8 @@ class TestAddCostItem(test.bootstrap.IFC4):
         item1 = ifcopenshell.api.run("cost.add_cost_item", self.file, cost_schedule=schedule)
         item2 = ifcopenshell.api.run("cost.add_cost_item", self.file, cost_item=item1)
         assert item2.is_a("IfcCostItem")
-        assert item2.Nests[0].RelatingObject == item1
+        assert ifcopenshell.util.element.get_nest(item2) == item1
+
+
+class TestAddCostItemIFC2X3(test.bootstrap.IFC2X3, TestAddCostItem):
+    pass
diff --git a/src/ifcopenshell-python/test/api/cost/test_add_cost_schedule.py b/src/ifcopenshell-python/test/api/cost/test_add_cost_schedule.py
index e02acb0ff6..5646b67601 100644
--- a/src/ifcopenshell-python/test/api/cost/test_add_cost_schedule.py
+++ b/src/ifcopenshell-python/test/api/cost/test_add_cost_schedule.py
@@ -33,3 +33,7 @@ class TestAddCostSchedule(test.bootstrap.IFC4):
         assert schedule.Name == "Foo"
         assert schedule.PredefinedType == "USERDEFINED"
         assert schedule.ObjectType == "FOO"
+
+
+class TestAddCostScheduleIFC2X3(test.bootstrap.IFC2X3, TestAddCostSchedule):
+    pass
diff --git a/src/ifcopenshell-python/test/api/cost/test_remove_cost_item.py b/src/ifcopenshell-python/test/api/cost/test_remove_cost_item.py
index e6768df8b8..96b7a11657 100644
--- a/src/ifcopenshell-python/test/api/cost/test_remove_cost_item.py
+++ b/src/ifcopenshell-python/test/api/cost/test_remove_cost_item.py
@@ -45,3 +45,7 @@ class TestRemoveCostItem(test.bootstrap.IFC4):
         assert not self.file.by_type("IfcCostItem")
         assert not self.file.by_type("IfcRelAssignsToControl")
         assert not self.file.by_type("IfcRelNests")
+
+
+class TestRemoveCostItemIFC2X3(test.bootstrap.IFC2X3, TestRemoveCostItem):
+    pass
diff --git a/src/ifcopenshell-python/test/api/cost/test_remove_cost_schedule.py b/src/ifcopenshell-python/test/api/cost/test_remove_cost_schedule.py
index 6b88d81a3f..7b2d534653 100644
--- a/src/ifcopenshell-python/test/api/cost/test_remove_cost_schedule.py
+++ b/src/ifcopenshell-python/test/api/cost/test_remove_cost_schedule.py
@@ -35,3 +35,7 @@ class TestRemoveCostSchedule(test.bootstrap.IFC4):
         assert not self.file.by_type("IfcCostItem")
         assert not self.file.by_type("IfcRelNests")
         assert not self.file.by_type("IfcRelAssignsToControl")
+
+
+class TestRemoveCostSchedule(test.bootstrap.IFC2X3, TestRemoveCostSchedule):
+    pass
diff --git a/src/ifcopenshell-python/test/api/document/test_add_information.py b/src/ifcopenshell-python/test/api/document/test_add_information.py
index 4d225e1f39..dcb7eacdb4 100644
--- a/src/ifcopenshell-python/test/api/document/test_add_information.py
+++ b/src/ifcopenshell-python/test/api/document/test_add_information.py
@@ -30,9 +30,10 @@ class TestAddInformation(test.bootstrap.IFC4):
     def test_adding_information_to_the_project(self):
         project = self.file.createIfcProject()
         element = ifcopenshell.api.run("document.add_information", self.file, parent=None)
-        rel = element.DocumentInfoForObjects[0]
+        rel = self.file.by_type("IfcRelAssociatesDocument")[0]
         assert rel.is_a("IfcRelAssociatesDocument")
-        assert rel.RelatedObjects[0] == project
+        assert rel.RelatingDocument == element
+        assert rel.RelatedObjects == (project,)
 
     def test_adding_a_subdocument(self):
         project = self.file.createIfcProject()
@@ -45,3 +46,7 @@ class TestAddInformation(test.bootstrap.IFC4):
         element2 = ifcopenshell.api.run("document.add_information", self.file, parent=parent)
         assert element in parent.IsPointer[0].RelatedDocuments
         assert element2 in parent.IsPointer[0].RelatedDocuments
+
+
+class TestAddInformationIFC2X3(test.bootstrap.IFC2X3, TestAddInformation):
+    pass
diff --git a/src/ifcopenshell-python/test/api/drawing/test_assign_product.py b/src/ifcopenshell-python/test/api/drawing/test_assign_product.py
index 78b10e5d76..12e57b7435 100644
--- a/src/ifcopenshell-python/test/api/drawing/test_assign_product.py
+++ b/src/ifcopenshell-python/test/api/drawing/test_assign_product.py
@@ -37,3 +37,7 @@ class TestAssignProduct(test.bootstrap.IFC4):
         ifcopenshell.api.run("drawing.assign_product", self.file, relating_product=wall, related_object=label)
         assert len(wall.ReferencedBy) == 1
         assert wall.ReferencedBy[0].RelatedObjects == (label,)
+
+
+class TestAssignProductIFC2X3(test.bootstrap.IFC2X3, TestAssignProduct):
+    pass
diff --git a/src/ifcopenshell-python/test/api/drawing/test_edit_text_literal.py b/src/ifcopenshell-python/test/api/drawing/test_edit_text_literal.py
index c0e9e73106..9da51a93e9 100644
--- a/src/ifcopenshell-python/test/api/drawing/test_edit_text_literal.py
+++ b/src/ifcopenshell-python/test/api/drawing/test_edit_text_literal.py
@@ -36,3 +36,7 @@ class TestEditTextLiteral(test.bootstrap.IFC4):
         assert text.Literal == "Literal"
         assert text.Path == "RIGHT"
         assert text.BoxAlignment == "middle"
+
+
+class TestEditTextLiteralIFC2X3(test.bootstrap.IFC2X3, TestEditTextLiteral):
+    pass
diff --git a/src/ifcopenshell-python/test/api/drawing/test_unassign_product.py b/src/ifcopenshell-python/test/api/drawing/test_unassign_product.py
index 39cc64ca16..c23e978b1c 100644
--- a/src/ifcopenshell-python/test/api/drawing/test_unassign_product.py
+++ b/src/ifcopenshell-python/test/api/drawing/test_unassign_product.py
@@ -27,3 +27,7 @@ class TestUnassignProduct(test.bootstrap.IFC4):
         ifcopenshell.api.run("drawing.assign_product", self.file, relating_product=wall, related_object=label)
         ifcopenshell.api.run("drawing.unassign_product", self.file, relating_product=wall, related_object=label)
         assert len(self.file.by_type("IfcRelAssignsToProduct")) == 0
+
+
+class TestUnassignProductIFC2X3(test.bootstrap.IFC2X3, TestUnassignProduct):
+    pass
diff --git a/src/ifcopenshell-python/test/api/type/test_map_type_representation.py b/src/ifcopenshell-python/test/api/type/test_map_type_representation.py
index a43430a040..a288c60197 100644
--- a/src/ifcopenshell-python/test/api/type/test_map_type_representation.py
+++ b/src/ifcopenshell-python/test/api/type/test_map_type_representation.py
@@ -49,3 +49,7 @@ class TestMapTypeRepresentations(test.bootstrap.IFC4):
         assert rep.RepresentationType == "MappedRepresentation"
         assert rep.Items[0].MappingSource == type.RepresentationMaps[0]
         assert len(self.file.by_type("IfcShapeRepresentation")) == 2
+
+
+class TestMapTypeRepresentationsIFC2X3(test.bootstrap.IFC2X3, TestMapTypeRepresentations):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_add_context_dependent_unit.py b/src/ifcopenshell-python/test/api/unit/test_add_context_dependent_unit.py
index b8892fc914..7d6887a893 100644
--- a/src/ifcopenshell-python/test/api/unit/test_add_context_dependent_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_add_context_dependent_unit.py
@@ -39,3 +39,7 @@ class TestAddContextDependentUnit(test.bootstrap.IFC4):
         assert unit.Dimensions.LuminousIntensityExponent == 7
         assert unit.UnitType == "LENGTHUNIT"
         assert unit.Name == "foobar"
+
+
+class TestAddContextDependentUnitIFC2X3(test.bootstrap.IFC2X3, TestAddContextDependentUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_add_conversion_based_unit.py b/src/ifcopenshell-python/test/api/unit/test_add_conversion_based_unit.py
index 0bfe848e0f..87f3513191 100644
--- a/src/ifcopenshell-python/test/api/unit/test_add_conversion_based_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_add_conversion_based_unit.py
@@ -20,7 +20,7 @@ import test.bootstrap
 import ifcopenshell.api
 
 
-class TestAddConversionBasedUnit(test.bootstrap.IFC4):
+class TestAddConversionBasedUnitIFC2X3(test.bootstrap.IFC2X3):
     def test_run(self):
         unit = ifcopenshell.api.run("unit.add_conversion_based_unit", self.file, name="foot")
         assert unit.is_a("IfcConversionBasedUnit")
@@ -40,6 +40,8 @@ class TestAddConversionBasedUnit(test.bootstrap.IFC4):
         assert si_unit.Prefix is None
         assert si_unit.Name == "METRE"
 
+
+class TestAddConversionBasedUnitIFC4(test.bootstrap.IFC4, TestAddConversionBasedUnitIFC2X3):
     def test_adding_a_unit_with_offset(self):
         unit = ifcopenshell.api.run("unit.add_conversion_based_unit", self.file, name="fahrenheit")
         assert unit.is_a("IfcConversionBasedUnitWithOffset")
diff --git a/src/ifcopenshell-python/test/api/unit/test_add_monetary_unit.py b/src/ifcopenshell-python/test/api/unit/test_add_monetary_unit.py
index af14cf0c2c..47d23505ec 100644
--- a/src/ifcopenshell-python/test/api/unit/test_add_monetary_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_add_monetary_unit.py
@@ -25,3 +25,7 @@ class TestAddMonetaryUnit(test.bootstrap.IFC4):
         unit = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="USD")
         assert unit.is_a("IfcMonetaryUnit")
         assert unit.Currency == "USD"
+
+
+class TestAddMonetaryUnitIFC2X3(test.bootstrap.IFC2X3, TestAddMonetaryUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py b/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py
index 8ebc7234ad..2c31cef495 100644
--- a/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_add_si_unit.py
@@ -26,3 +26,7 @@ class TestAddSIUnit(test.bootstrap.IFC4):
         assert unit.UnitType == "LENGTHUNIT"
         assert unit.Name == "METRE"
         assert unit.Prefix == "MILLI"
+
+
+class TestAddSIUnitIFC2X3(test.bootstrap.IFC2X3, TestAddSIUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_assign_unit.py b/src/ifcopenshell-python/test/api/unit/test_assign_unit.py
index 198e8b362a..c16c423a9a 100644
--- a/src/ifcopenshell-python/test/api/unit/test_assign_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_assign_unit.py
@@ -23,8 +23,8 @@ import ifcopenshell.api
 class TestAssignUnit(test.bootstrap.IFC4):
     def test_run(self):
         project = self.file.createIfcProject()
-        unit1 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="FOO")
-        unit2 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="BAR")
+        unit1 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="USD")
+        unit2 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="JPY")
         assignment = ifcopenshell.api.run("unit.assign_unit", self.file, units=[unit1, unit2])
         assert project.UnitsInContext == assignment
         assert assignment.is_a("IfcUnitAssignment")
@@ -33,11 +33,15 @@ class TestAssignUnit(test.bootstrap.IFC4):
 
     def test_assign_units_to_an_existing_assignment(self):
         project = self.file.createIfcProject()
-        unit1 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="FOO")
-        unit2 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="BAR")
+        unit1 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="USD")
+        unit2 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="JPY")
         assignment1 = ifcopenshell.api.run("unit.assign_unit", self.file, units=[unit1])
         assignment2 = ifcopenshell.api.run("unit.assign_unit", self.file, units=[unit2])
         assert project.UnitsInContext == assignment1
         assert assignment1 == assignment2
         assert unit1 in assignment1.Units
         assert unit2 in assignment1.Units
+
+
+class TestAssignUnitIFC2X3(test.bootstrap.IFC2X3, TestAssignUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_edit_derived_unit.py b/src/ifcopenshell-python/test/api/unit/test_edit_derived_unit.py
index 026163cf0e..3657fb0511 100644
--- a/src/ifcopenshell-python/test/api/unit/test_edit_derived_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_edit_derived_unit.py
@@ -31,3 +31,7 @@ class TestEditDerivedUnit(test.bootstrap.IFC4):
         )
         assert unit.UnitType == "USERDEFINED"
         assert unit.UserDefinedType == "UserDefinedType"
+
+
+class TestEditDerivedUnitIFC2X3(test.bootstrap.IFC2X3, TestEditDerivedUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_edit_monetary_unit.py b/src/ifcopenshell-python/test/api/unit/test_edit_monetary_unit.py
index ef5d10becb..a2d780bfb7 100644
--- a/src/ifcopenshell-python/test/api/unit/test_edit_monetary_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_edit_monetary_unit.py
@@ -23,5 +23,9 @@ import ifcopenshell.api
 class TestEditMonetaryUnit(test.bootstrap.IFC4):
     def test_run(self):
         unit = self.file.createIfcMonetaryUnit()
-        ifcopenshell.api.run("unit.edit_monetary_unit", self.file, unit=unit, attributes={"Currency": "FOO"})
-        assert unit.Currency == "FOO"
+        ifcopenshell.api.run("unit.edit_monetary_unit", self.file, unit=unit, attributes={"Currency": "USD"})
+        assert unit.Currency == "USD"
+
+
+class TestEditMonetaryUnitIFC2X3(test.bootstrap.IFC2X3, TestEditMonetaryUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_edit_named_unit.py b/src/ifcopenshell-python/test/api/unit/test_edit_named_unit.py
index 4aba4a43e3..ffaca2d32b 100644
--- a/src/ifcopenshell-python/test/api/unit/test_edit_named_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_edit_named_unit.py
@@ -20,7 +20,7 @@ import test.bootstrap
 import ifcopenshell.api
 
 
-class TestEditNamedUnit(test.bootstrap.IFC4):
+class TestEditNamedUnitIFC2X3(test.bootstrap.IFC2X3):
     def test_edit_context_dependent_unit(self):
         unit = self.file.createIfcContextDependentUnit()
         unit.Dimensions = self.file.createIfcDimensionalExponents()
@@ -59,6 +59,8 @@ class TestEditNamedUnit(test.bootstrap.IFC4):
         assert unit.UnitType == "LENGTHUNIT"
         assert unit.Name == "Name"
 
+
+class TestEditNamedUnitIFC4(test.bootstrap.IFC4, TestEditNamedUnitIFC2X3):
     def test_edit_conversion_based_unit_with_offset(self):
         unit = self.file.createIfcConversionBasedUnitWithOffset()
         unit.Dimensions = self.file.createIfcDimensionalExponents()
diff --git a/src/ifcopenshell-python/test/api/unit/test_remove_unit.py b/src/ifcopenshell-python/test/api/unit/test_remove_unit.py
index c6a885c6bc..c53d66e2eb 100644
--- a/src/ifcopenshell-python/test/api/unit/test_remove_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_remove_unit.py
@@ -47,3 +47,7 @@ class TestRemoveUnit(test.bootstrap.IFC4):
         unit = ifcopenshell.api.run("unit.add_conversion_based_unit", self.file, name="foot")
         ifcopenshell.api.run("unit.remove_unit", self.file, unit=unit)
         assert len([e for e in self.file]) == 0
+
+
+class TestRemoveUnitIFC2X3(test.bootstrap.IFC2X3, TestRemoveUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/unit/test_unassign_unit.py b/src/ifcopenshell-python/test/api/unit/test_unassign_unit.py
index 0e0d0f71a3..13087d9e00 100644
--- a/src/ifcopenshell-python/test/api/unit/test_unassign_unit.py
+++ b/src/ifcopenshell-python/test/api/unit/test_unassign_unit.py
@@ -23,8 +23,8 @@ import ifcopenshell.api
 class TestUnassignUnit(test.bootstrap.IFC4):
     def test_run(self):
         project = self.file.createIfcProject()
-        unit1 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="FOO")
-        unit2 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="BAR")
+        unit1 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="USD")
+        unit2 = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="JPY")
         assignment = ifcopenshell.api.run("unit.assign_unit", self.file, units=[unit1, unit2])
         ifcopenshell.api.run("unit.unassign_unit", self.file, units=[unit1])
         assert unit1 not in assignment.Units
@@ -32,11 +32,15 @@ class TestUnassignUnit(test.bootstrap.IFC4):
 
     def test_unassigning_the_last_unit(self):
         project = self.file.createIfcProject()
-        unit = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="FOO")
+        unit = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="USD")
         ifcopenshell.api.run("unit.assign_unit", self.file, units=[unit])
         ifcopenshell.api.run("unit.unassign_unit", self.file, units=[unit])
         assert project.UnitsInContext is None
 
     def test_doing_nothing_if_the_unit_is_not_assigned(self):
-        unit = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="FOO")
+        unit = ifcopenshell.api.run("unit.add_monetary_unit", self.file, currency="USD")
         assert ifcopenshell.api.run("unit.unassign_unit", self.file, units=[unit]) is None
+
+
+class TestUnassignUnitIFC2X3(test.bootstrap.IFC2X3, TestUnassignUnit):
+    pass
diff --git a/src/ifcopenshell-python/test/api/void/test_add_filling.py b/src/ifcopenshell-python/test/api/void/test_add_filling.py
index 46ce089190..c29da2323d 100644
--- a/src/ifcopenshell-python/test/api/void/test_add_filling.py
+++ b/src/ifcopenshell-python/test/api/void/test_add_filling.py
@@ -43,3 +43,7 @@ class TestAddFilling(test.bootstrap.IFC4):
         ifcopenshell.api.run("void.add_filling", self.file, opening=opening2, element=door)
         assert not opening1.HasFillings
         assert opening2.HasFillings[0].RelatedBuildingElement == door
+
+
+class TestAddFillingIFC2X3(test.bootstrap.IFC2X3, TestAddFilling):
+    pass
diff --git a/src/ifcopenshell-python/test/api/void/test_add_opening.py b/src/ifcopenshell-python/test/api/void/test_add_opening.py
index 357cc300fb..4a168eead0 100644
--- a/src/ifcopenshell-python/test/api/void/test_add_opening.py
+++ b/src/ifcopenshell-python/test/api/void/test_add_opening.py
@@ -77,3 +77,7 @@ class TestAddOpening(test.bootstrap.IFC4):
         opening.ObjectPlacement = placement
         ifcopenshell.api.run("void.add_opening", self.file, opening=opening, element=wall)
         assert opening.ObjectPlacement == placement
+
+
+class TestAddOpeningIFC2X3(test.bootstrap.IFC2X3, TestAddOpening):
+    pass
diff --git a/src/ifcopenshell-python/test/api/void/test_remove_opening.py b/src/ifcopenshell-python/test/api/void/test_remove_opening.py
index 6a121a2a61..fd176cb7fc 100644
--- a/src/ifcopenshell-python/test/api/void/test_remove_opening.py
+++ b/src/ifcopenshell-python/test/api/void/test_remove_opening.py
@@ -47,3 +47,7 @@ class TestRemoveOpening(test.bootstrap.IFC4):
         assert len(self.file.by_type("IfcRelFillsElement")) == 0
         assert wall
         assert door
+
+
+class TestRemoveOpeningIFC2X3(test.bootstrap.IFC2X3, TestRemoveOpening):
+    pass