fixup! Add test to deserialize unsigned int

tests/unsigned_int.rs

@@ -1,3 +1,7 @@
+#![cfg(feature = "preserve_order")]
+
+extern crate indexmap;
+
 #[derive(serde::Deserialize, Eq, PartialEq, Debug)]
 struct Container<T> {
     inner: T,
@@ -16,20 +20,20 @@ impl Default for Unsigned {
 
 impl From<Unsigned> for config::ValueKind {
     fn from(unsigned: Unsigned) -> Self {
-        let mut properties = std::collections::HashMap::default();
+        let mut properties = indexmap::IndexMap::new();
         properties.insert(
             "unsigned".to_string(),
             config::Value::from(unsigned.unsigned),
         );
 
-        Self::Table(properties)
+        Self::Table(properties.into())
     }
 }
 
 #[test]
 fn test_deser_unsigned_int() {
     let container = Container {
-        inner: Unsigned::default()
+        inner: Unsigned::default(),
     };
 
     let built = config::Config::builder()