fix(security): symmetric nonce, update unit tests

Signed-off-by: fufesou <linlong1266@gmail.com>

src/config.rs

@@ -3274,6 +3274,11 @@ mod tests {
         original_hard_settings: HashMap<String, String>,
     }
 
+    struct ConfigFileRestoreGuard {
+        path: PathBuf,
+        original_content: Option<Vec<u8>>,
+    }
+
     impl ConfigStateTestGuard {
         fn new(config: Config, hard_settings: HashMap<String, String>) -> Self {
             let original_config = Config::get();
@@ -3294,6 +3299,29 @@ mod tests {
         }
     }
 
+    impl ConfigFileRestoreGuard {
+        fn new(path: PathBuf) -> Self {
+            let original_content = fs::read(&path).ok();
+            Self {
+                path,
+                original_content,
+            }
+        }
+    }
+
+    impl Drop for ConfigFileRestoreGuard {
+        fn drop(&mut self) {
+            if let Some(content) = &self.original_content {
+                if let Some(parent) = self.path.parent() {
+                    fs::create_dir_all(parent).ok();
+                }
+                fs::write(&self.path, content).ok();
+            } else {
+                fs::remove_file(&self.path).ok();
+            }
+        }
+    }
+
     fn with_config_and_hard_settings<R>(
         config: Config,
         hard_settings: HashMap<String, String>,
@@ -3522,6 +3550,8 @@ mod tests {
 
     #[test]
     fn test_config2_store_keeps_existing_unlock_pin_when_pin_is_unchanged() {
+        let _guard = CONFIG_STATE_TEST_LOCK.lock().unwrap();
+        let _file_guard = ConfigFileRestoreGuard::new(Config::file_("2"));
         let pin = "123456";
         let original_unlock_pin =
             encrypt_str_or_original(pin, PASSWORD_ENC_VERSION, ENCRYPT_MAX_LEN);