message: impl PartialEq for NegativeCycle
diff: @@ -535,7 +535,7 @@ impl<N> Cycle<N> {
  }
  }
  /// An algorithm error: a cycle of negative weights was found in the graph.
  -#[derive(Clone, Debug)]
  +#[derive(Clone, Debug, PartialEq)]
  pub struct NegativeCycle(());
  /// [Generic] Compute shortest paths from node `source` to all other.
  