test build extens test build extend object base model us case factori creat us object extens model us case factori creat us object point model us case factori build extens point base extensionpoint ad base model facad extens point base contain point object extend model us case factori build extend base extens point extend ad extens model facad extens contain extend extend ad correct extensionpoint model facad extens point extend contain point model facad extens point extend size model uml factori delet base extens point delet base us model uml factori remov point extend delet us model uml factori remov extend 