message: MAINT: Add test for using Dot with StableGraph
diff: @@ -13,6 +13,7 @@ use petgraph::visit::{
  IntoNodeReferences,
  IntoEdgeReferences,
  };
  +use petgraph::dot::Dot;
  use itertools::assert_equal;
  @@ -259,3 +260,21 @@ fn iterators_undir() {
  vec![],
  );
  }
  +
  +#[test]
  +fn dot() {
  + let mut gr = StableGraph::new();
  + let a = gr.add_node("x");
  + let b = gr.add_node("y");
  + gr.add_edge(a, a, "10");
  + gr.add_edge(a, b, "20");
  + let dot_output = format!("{}", Dot::new(&gr));
  + assert_eq!(dot_output,
  +r#"digraph {
  + 0 [label="x"]
  + 1 [label="y"]
  + 0 -> 0 [label="10"]
  + 0 -> 1 [label="20"]
  +}
  +"#);
  +}
  