From e7619a4ca36cc67e7f00833aaab216599c986db8 Mon Sep 17 00:00:00 2001
From: Vitor Enes <vitorenesduarte@gmail.com>
Date: Sat, 9 Mar 2019 18:24:38 +0000
Subject: [PATCH] Add arbitrary simple shrink tests

---
 src/arbitrary.rs | 30 ++++++++++++++++++++++++++++++
 src/multiset.rs  |  4 +++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/arbitrary.rs b/src/arbitrary.rs
index 71828f1..90bf495 100644
--- a/src/arbitrary.rs
+++ b/src/arbitrary.rs
@@ -38,3 +38,33 @@ impl<T: Actor + Arbitrary> Arbitrary for VClock<T> {
         Box::new(vec.shrink().map(|v| VClock::from_vec(v)))
     }
 }
+
+#[cfg(test)]
+mod test {
+    use crate::*;
+    use quickcheck::{Arbitrary, StdThreadGen};
+
+    #[test]
+    fn multiset_shrink() {
+        let count = shrink_count::<MultiSet<u64>>();
+        assert!(count > 0);
+    }
+
+    #[test]
+    fn dot_shrink() {
+        let count = shrink_count::<Dot<u64>>();
+        assert!(count == 0);
+    }
+
+    #[test]
+    fn vclock_shrink() {
+        let count = shrink_count::<VClock<u64>>();
+        assert!(count > 0);
+    }
+
+    fn shrink_count<T: Arbitrary>() -> usize {
+        let mut g = StdThreadGen::new(100);
+        let instance: T = Arbitrary::arbitrary(&mut g);
+        instance.shrink().count()
+    }
+}
diff --git a/src/multiset.rs b/src/multiset.rs
index 4bd13d8..19e42a6 100644
--- a/src/multiset.rs
+++ b/src/multiset.rs
@@ -45,7 +45,9 @@ impl<T: Ord> MultiSet<T> {
     /// assert_eq!(mset.count(&17), 1);
     /// ```
     pub fn singleton(elem: T) -> Self {
-        Self::from_vec(vec![(elem, 1)])
+        let mut mset = Self::new();
+        mset.add_elem(elem);
+        mset
     }
 
     /// Creates a new `MultiSet` from a vector of tuples (elem, elem count).