@Test
public void doesNotReplaceUnchangedShapes() {

    ShapeId shapeId = ShapeId.from("ns.foo#id1");
    StringShape shape = StringShape.builder()
            .id(shapeId)
            .addTrait(new SensitiveTrait())
            .build();
    Model model = Model.builder().addShape(shape).build();
    ModelTransformer transformer = ModelTransformer.create();
    transformer.mapTraits(model, (s, t) -> t);
}