diff --git a/test_suite/tests/test_ser.rs b/test_suite/tests/test_ser.rs
index ae10b26b..8bf833da 100644
--- a/test_suite/tests/test_ser.rs
+++ b/test_suite/tests/test_ser.rs
@@ -9,7 +9,7 @@
 #[macro_use]
 extern crate serde_derive;
 
-use std::collections::{BTreeMap, HashMap, HashSet};
+use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 use std::net;
 use std::path::{Path, PathBuf};
 use std::time::Duration;
@@ -170,6 +170,17 @@ declare_tests! {
             Token::SeqEnd,
         ],
     }
+    test_btreeset {
+        BTreeSet::<isize>::new() => &[
+            Token::Seq { len: Some(0) },
+            Token::SeqEnd,
+        ],
+        btreeset![1] => &[
+            Token::Seq { len: Some(1) },
+                Token::I32(1),
+            Token::SeqEnd,
+        ],
+    }
     test_hashset {
         HashSet::<isize>::new() => &[
             Token::Seq { len: Some(0) },