chore: checkpoint before Python removal

vendor/litemap/tests/serde.rs

@@ -0,0 +1,22 @@
+// This file is part of ICU4X. For terms of use, please see the file
+// called LICENSE at the top level of the ICU4X source tree
+// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
+
+use litemap::LiteMap;
+
+#[test]
+fn test_ser() {
+    let mut map = LiteMap::new_vec();
+    map.insert(1, "jat");
+    map.insert(4, "sei");
+    map.insert(3, "saam");
+    map.insert(2, "ji");
+
+    let json_string = serde_json::to_string(&map).unwrap();
+
+    assert_eq!(json_string, r#"{"1":"jat","2":"ji","3":"saam","4":"sei"}"#);
+
+    let new_map = serde_json::from_str(&json_string).unwrap();
+
+    assert_eq!(map, new_map);
+}