} else if len(stmt.Schema.PrimaryFields) != 1 {
		t.Errorf("should have only one primary field with embedded struct, but got %v", len(stmt.Schema.PrimaryFields))
	}

	for _, name := range []string{"user_id", "user_name", "user_email"} {
		if !DB.Migrator().HasColumn(&HNPost{}, name) {
			t.Errorf("should has prefixed column %v", name)
		}
	}

	// save embedded struct
	DB.Save(&HNPost{BasePost: BasePost{Title: "news"}})