diff --git a/backup/src/delta.rs b/backup/src/delta.rs
index 85b36a0..cc831ac 100644
--- a/backup/src/delta.rs
+++ b/backup/src/delta.rs
@@ -230,4 +230,16 @@ mod tests {
         assert_eq!(expected, a.union(&b));
         assert_eq!(expected, b.union(&a));
     }
+
+    #[test]
+    fn test_union_full_revert() {
+        let a = Delta::default().with_added("dir_1", ["file1", "file2"]);
+        let b = Delta::default().with_removed("dir_1", ["file1", "file2"]);
+
+        let expected = Delta::default().with_removed("dir_1", ["file1", "file2"]);
+        assert_eq!(expected, a.union(&b));
+
+        let expected = Delta::default().with_added("dir_1", ["file1", "file2"]);
+        assert_eq!(expected, b.union(&a));
+    }
 }