Swapping a Blender material for another is now auto synchronised.

src/blenderbim/test/bim/feature/project.feature

@@ -401,3 +401,18 @@ Scenario: Export IFC - with changed style colour synchronised
     And an empty Blender session is started
     And I press "bim.load_project(filepath='{cwd}/test/files/export.ifc')"
     Then the material "Material" colour is "1,0,0,1"
+
+Scenario: Export IFC - with changed style element synchronised
+    Given an empty IFC project
+    And I add a cube
+    And the object "Cube" is selected
+    And I add a material
+    And I set "scene.BIMRootProperties.ifc_class" to "IfcWall"
+    And I press "bim.assign_class"
+    And the object "IfcWall/Cube" is selected
+    When I add a material
+    And the material "Material.001" colour is set to "1,0,0,1"
+    And I press "export_ifc.bim(filepath='{cwd}/test/files/export.ifc')"
+    And an empty Blender session is started
+    And I press "bim.load_project(filepath='{cwd}/test/files/export.ifc')"
+    Then the material "Material.001" colour is "1,0,0,1"

src/blenderbim/test/bim/test_feature.py

@@ -91,6 +91,7 @@ def i_add_a_sun():
 
 
 @given("I add a material")
+@when("I add a material")
 def i_add_a_material():
     bpy.context.active_object.active_material = bpy.data.materials.new("Material")
 

src/blenderbim/test/core/test_geometry.py

@@ -74,6 +74,7 @@ class TestAddRepresentation:
             styles=["style"],
             should_use_presentation_style_assignment=False,
         ).should_be_called()
+        geometry.record_object_materials("obj").should_be_called()
 
         # Assign representation to product
         ifc.run("geometry.assign_representation", product="element", representation="representation").should_be_called()

src/blenderbim/test/tool/test_geometry.py

@@ -352,6 +352,19 @@ class TestLink(NewFile):
         assert obj.BIMMeshProperties.ifc_definition_id == element.id()
 
 
+class TestRecordObjectMaterials(NewFile):
+    def test_run(self):
+        obj = bpy.data.objects.new("Object", bpy.data.meshes.new("Mesh"))
+        ifc = ifcopenshell.file()
+        tool.Ifc.set(ifc)
+        style = ifc.createIfcSurfaceStyle()
+        material = bpy.data.materials.new("Material")
+        material.BIMMaterialProperties.ifc_style_id = style.id()
+        obj.data.materials.append(material)
+        subject.record_object_materials(obj)
+        assert obj.data.BIMMeshProperties.material_checksum == str([style.id()])
+
+
 class TestRecordObjectPosition(NewFile):
     def test_run(self):
         obj = bpy.data.objects.new("Object", None)