message: Add additional test for A*
  The new test uses an admissible but inconsistent heuristic. The current
  implementation of A* fails to find the optimal solution
diff: @@ -574,6 +574,30 @@ fn test_astar_manhattan_heuristic() {
  }
  }
  +#[test]
  +fn test_astar_admissible_inconsistent() {
  + let mut g = Graph::new();
  + let a = g.add_node("A");
  + let b = g.add_node("B");
  + let c = g.add_node("C");
  + let d = g.add_node("D");
  + g.add_edge(a, b, 3);
  + g.add_edge(b, c, 3);
  + g.add_edge(c, d, 3);
  + g.add_edge(a, c, 8);
  + g.add_edge(a, d, 10);
  +
  + let admissible_inconsistent = |n: NodeIndex| match g[n] {
  + "A" => 9,
  + "B" => 6,
  + "C" => 0,
  + &_ => 0,
  + };
  +
  + let optimal = astar(&g, a, |n| n == d, |e| *e.weight(), admissible_inconsistent);
  + assert_eq!(optimal, Some((9, vec![a, b, c, d])));
  +}
  +
  #[cfg(feature = "generate")]
  #[test]
  fn test_generate_undirected() {
  