///|
fn case_input_graph_json() -> String {
  "{\"id\":\"root\",\"layoutOptions\":{\"algorithm\":\"disco\"},\"children\":[{\"id\":\"n1\",\"width\":60,\"height\":30},{\"id\":\"n2\",\"width\":60,\"height\":30},{\"id\":\"n3\",\"width\":60,\"height\":30}],\"edges\":[{\"id\":\"e1\",\"sources\":[\"n1\"],\"targets\":[\"n2\"]},{\"id\":\"e2\",\"sources\":[\"n2\"],\"targets\":[\"n3\"]}]}"
}