Fix bug where style colours were not auto synchronised.

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

@@ -387,3 +387,17 @@ Scenario: Export IFC - with changed object scale synchronised
     And an empty Blender session is started
     And I press "bim.load_project(filepath='{cwd}/test/files/export.ifc')"
     Then the object "IfcWall/Cube" dimensions are "4,4,4"
+
+Scenario: Export IFC - with changed style colour 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 the material "Material" 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" colour is "1,0,0,1"

src/blenderbim/test/bim/test_feature.py

@@ -95,6 +95,14 @@ def i_add_a_material():
     bpy.context.active_object.active_material = bpy.data.materials.new("Material")
 
 
+@given(parsers.parse('the material "{name}" colour is set to "{colour}"'))
+@when(parsers.parse('the material "{name}" colour is set to "{colour}"'))
+def the_material_name_colour_is_set_to_colour(name, colour):
+    obj = the_material_name_exists(name)
+    obj.diffuse_color = [float(c) for c in colour.split(",")]
+    blenderbim.bim.handler.color_callback(obj, None)
+
+
 @given("I add an array modifier")
 def i_add_a_cube():
     bpy.ops.object.modifier_add(type="ARRAY")
@@ -385,6 +393,12 @@ def the_material_name_is_not_an_ifc_material(name):
     assert id == 0, f"The ID is {id}"
 
 
+@then(parsers.parse('the material "{name}" colour is "{colour}"'))
+def the_material_name_colour_is_set_to_colour(name, colour):
+    diffuse_color = list(the_material_name_exists(name).diffuse_color)
+    assert diffuse_color == [float(c) for c in colour.split(",")], f"The colour is {diffuse_color}"
+
+
 @then(parsers.parse('the object "{name}" has "{number}" vertices'))
 def the_object_name_has_number_vertices(name, number):
     total = len(the_object_name_exists(name).data.vertices)