FEAT: Implement shrink for StableGraph
diff --git a/src/quickcheck.rs b/src/quickcheck.rs
index e2f4878..18d40c7 100644
--- a/src/quickcheck.rs
+++ b/src/quickcheck.rs
@@ -138,6 +138,29 @@
}
gr
}
+
+ // shrink the graph by splitting it in two by a very
+ // simple algorithm, just even and odd node indices
+ fn shrink(&self) -> Box<Iterator<Item=Self>> {
+ let self_ = self.clone();
+ Box::new((0..2).filter_map(move |x| {
+ let gr = self_.filter_map(|i, w| {
+ if i.index() % 2 == x {
+ Some(w.clone())
+ } else {
+ None
+ }
+ },
+ |_, w| Some(w.clone())
+ );
+ // make sure we shrink
+ if gr.node_count() < self_.node_count() {
+ Some(gr)
+ } else {
+ None
+ }
+ }))
+ }
}
/// `Arbitrary` for `GraphMap` creates a graph by selecting a node count
