1 files changed, 27 insertions, 0 deletions
diff --git a/vendor/petgraph/tests/utils/qc.rs b/vendor/petgraph/tests/utils/qc.rs
new file mode 100644
index 000000000..f33562528
--- /dev/null
+++ b/vendor/petgraph/tests/utils/qc.rs
@@ -0,0 +1,27 @@
+use quickcheck::{Arbitrary, Gen, StdGen};
+use std::ops::Deref;
+
+#[derive(Copy, Clone, Debug)]
+/// quickcheck Arbitrary adaptor - half the size of `T` on average
+pub struct Small<T>(pub T);
+
+impl<T> Deref for Small<T> {
+    type Target = T;
+    fn deref(&self) -> &T {
+        &self.0
+    }
+}
+
+impl<T> Arbitrary for Small<T>
+where
+    T: Arbitrary,
+{
+    fn arbitrary<G: Gen>(g: &mut G) -> Self {
+        let sz = g.size() / 2;
+        Small(T::arbitrary(&mut StdGen::new(g, sz)))
+    }
+
+    fn shrink(&self) -> Box<dyn Iterator<Item = Self>> {
+        Box::new((**self).shrink().map(Small))
+    }
+}