diff --git a/src/persistence.rs b/src/persistence.rs
index cf3b439..9fcb75e 100644
--- a/src/persistence.rs
+++ b/src/persistence.rs
@@ -84,7 +84,7 @@ struct FileManager {
 
 impl FileManager {
     async fn init(path: &str) -> std::io::Result<Self> {
-        let file = File::open(path).await?;
+        let file = File::options().read(true).append(true).open(path).await?;
         Ok(Self {
             file: Mutex::new(file),
         })
@@ -196,8 +196,14 @@ mod tests {
             node.keypair.to_keypair_bytes(),
             retrieved_node.keypair.to_keypair_bytes()
         );
-        assert_eq!(node.joined_at, retrieved_node.joined_at);
-
+        assert_eq!(
+            node.joined_at.duration_since(UNIX_EPOCH).unwrap().as_secs(),
+            retrieved_node
+                .joined_at
+                .duration_since(UNIX_EPOCH)
+                .unwrap()
+                .as_secs()
+        );
         remove_file(get_test_file_name(function_name)).await?;
 
         Ok(())