Make BatchHandle::add return option of old bid as serde_json::Value

src/proto/batch/mod.rs

@@ -221,14 +221,13 @@ impl<'a, S: Read + Write> BatchHandle<'a, S> {
 
     /// Add the given job to the batch.
     ///
-    /// Should the submitted job - for whatever reason - already have a `bid` (batch ID) specified
-    /// in its custom hash, this value will be overwritten by the ID of the batch this job is being added to
-    /// with the old value returned as `Some(<old value here>)`.
-    pub fn add(&mut self, mut job: Job) -> Result<Option<String>, Error> {
+    /// Should the submitted job - for whatever reason - already have a `bid` key present in its custom hash,
+    /// this value will be overwritten by the ID of the batch this job is being added to with the old value 
+    /// returned as `Some(<old value here>)`.
+    pub fn add(&mut self, mut job: Job) -> Result<Option<serde_json::Value>, Error> {
         let bid = job
             .custom
-            .insert("bid".into(), self.bid.clone().into())
-            .map(|bid| bid.to_string());
+            .insert("bid".into(), self.bid.clone().into());
         self.prod.enqueue(job).map(|_| bid)
     }
 

tests/real/enterprise.rs

@@ -588,7 +588,7 @@ fn test_batch_of_jobs_can_be_initiated() {
 
     assert!(b.add(job_1).unwrap().is_none());
     assert!(b.add(job_2).unwrap().is_none());
-    assert_eq!(b.add(job_3).unwrap().unwrap(), "check-check");
+    assert_eq!(b.add(job_3).unwrap().unwrap(), Value::from("check-check"));
     b.commit().unwrap();
 
     // The batch has been committed, let's see its status: