if age != ((1+10+20)*2 + 30) {
		t.Errorf("Invalid age, got %v", age)
	}
}

func TestRowsWithGroup(t *testing.T) {
	users := []User{
		{Name: "having_user_1", Age: 1},
		{Name: "having_user_2", Age: 10},
		{Name: "having_user_1", Age: 20},
		{Name: "having_user_1", Age: 30},
	}

	DB.Create(&users)