diff --git a/services/commtest/tests/backup/add_attachments.rs b/services/commtest/tests/backup/add_attachments.rs
new file mode 100644
index 000000000..5570e9312
--- /dev/null
+++ b/services/commtest/tests/backup/add_attachments.rs
@@ -0,0 +1,53 @@
+#[path = "./backup_utils.rs"]
+mod backup_utils;
+#[path = "../lib/tools.rs"]
+mod tools;
+
+use crate::backup_utils::{proto::AddAttachmentsRequest, BackupServiceClient};
+
+use tonic::Request;
+
+use crate::backup_utils::BackupData;
+use crate::tools::{Error, ATTACHMENT_DELIMITER};
+
+// log_index = None means that we add attachments to the backup
+// log_index = Some(x) means that we add attachments to a specific log
+pub async fn run(
+  client: &mut BackupServiceClient<tonic::transport::Channel>,
+  backup_data: &BackupData,
+  log_index: Option<usize>,
+) -> Result<(), Error> {
+  let cloned_user_id = backup_data.user_id.clone();
+  let cloned_backup_id = backup_data.backup_item.id.clone();
+  let log_id: String = match log_index {
+    Some(index) => {
+      let log_id = backup_data.log_items[index].id.clone();
+      println!("add attachments for log {}/{}", index, log_id);
+      log_id
+    },
+    None => {
+      println!("add attachments for backup");
+      String::new()
+    },
+  };
+  
+  let holders: String = match log_index {
+    Some(log_index) => backup_data.log_items[log_index]
+      .attachments_holders
+      .join(ATTACHMENT_DELIMITER),
+    None => backup_data
+      .backup_item
+      .attachments_holders
+      .join(ATTACHMENT_DELIMITER),
+  };
+
+  client
+    .add_attachments(Request::new(AddAttachmentsRequest {
+      user_id: cloned_user_id,
+      backup_id: cloned_backup_id,
+      log_id,
+      holders,
+    }))
+    .await?;
+  Ok(())
+}
diff --git a/services/commtest/tests/lib/tools.rs b/services/commtest/tests/lib/tools.rs
index fb382fdab..6df15de8d 100644
--- a/services/commtest/tests/lib/tools.rs
+++ b/services/commtest/tests/lib/tools.rs
@@ -1,22 +1,22 @@
 use bytesize::ByteSize;
 
 #[allow(dead_code)]
 pub fn generate_nbytes(number_of_bytes: usize, predefined_byte_value: Option<u8>) -> Vec<u8> {
   let byte_value = predefined_byte_value.unwrap_or(b'A');
   return vec![byte_value; number_of_bytes];
 }
 
 #[derive(
   Debug, derive_more::Display, derive_more::From, derive_more::Error,
 )]
 pub enum Error {
   #[display(...)]
   Proto(std::io::Error),
   #[display(...)]
   Tonic(tonic::transport::Error),
   #[display(...)]
   TonicStatus(tonic::Status),
 }
 
 #[allow(dead_code)]
-pub const ATTACHMENT_DELIMITER: char = ';';
+pub const ATTACHMENT_DELIMITER: &str = ";";