Just to have a chance to try it out: Switch to proptest.

src/messages/utils.rs

@@ -1,32 +1,15 @@
-#[cfg(test)]
-use quickcheck::{Arbitrary, Gen};
-
-#[cfg(test)]
-pub fn arbitrary_socks_string(g: &mut Gen) -> String {
-    loop {
-        let mut potential = String::arbitrary(g);
-
-        potential.truncate(255);
-        let bytestring = potential.as_bytes();
-
-        if !bytestring.is_empty() && bytestring.len() < 256 {
-            return potential;
-        }
-    }
-}
-
 #[doc(hidden)]
 #[macro_export]
 macro_rules! standard_roundtrip {
     ($name: ident, $t: ty) => {
-        #[cfg(test)]
-        quickcheck! {
-            fn $name(xs: $t) -> bool {
+        proptest! {
+            #[test]
+            fn $name(xs: $t) {
                 let mut buffer = vec![];
                 task::block_on(xs.write(&mut buffer)).unwrap();
                 let mut cursor = Cursor::new(buffer);
                 let ys = <$t>::read(&mut cursor);
-                xs == task::block_on(ys).unwrap()
+                assert_eq!(xs, task::block_on(ys).unwrap());
             }
         }
     };