Correct fetching Bitcoin TXs in the processor docker tests

tests/processor/src/lib.rs

@@ -416,16 +416,27 @@ impl Coordinator {
     }
   }
 
-  pub async fn get_transaction(&self, ops: &DockerOperations, tx: &[u8]) -> Option<Vec<u8>> {
+  pub async fn get_published_transaction(
+    &self,
+    ops: &DockerOperations,
+    tx: &[u8],
+  ) -> Option<Vec<u8>> {
     let rpc_url = network_rpc(self.network, ops, &self.network_handle);
     match self.network {
       NetworkId::Bitcoin => {
         use bitcoin_serai::{bitcoin::consensus::Encodable, rpc::Rpc};
 
         let rpc =
           Rpc::new(rpc_url).await.expect("couldn't connect to the coordinator's Bitcoin RPC");
+
+        // Bitcoin publishes a 0-byte TX ID to reduce variables
+        // Accordingly, read the mempool to find the (presumed relevant) TX
+        let entries: Vec<String> =
+          rpc.rpc_call("getrawmempool", serde_json::json!([false])).await.unwrap();
+        assert_eq!(entries.len(), 1, "more than one entry in the mempool, so unclear which to get");
+
         let mut hash = [0; 32];
-        hash.copy_from_slice(tx);
+        hash.copy_from_slice(&hex::decode(&entries[0]).unwrap());
         if let Ok(tx) = rpc.get_transaction(&hash).await {
           let mut buf = vec![];
           tx.consensus_encode(&mut buf).unwrap();

tests/processor/src/tests/send.rs

@@ -261,12 +261,12 @@ fn send_test() {
       let participating =
         participating.iter().map(|p| usize::from(u16::from(*p) - 1)).collect::<HashSet<_>>();
       for participant in &participating {
-        assert!(coordinators[*participant].get_transaction(&ops, &tx_id).await.is_some());
+        assert!(coordinators[*participant].get_published_transaction(&ops, &tx_id).await.is_some());
       }
 
       // Publish this transaction to the left out nodes
       let tx = coordinators[*participating.iter().next().unwrap()]
-        .get_transaction(&ops, &tx_id)
+        .get_published_transaction(&ops, &tx_id)
         .await
         .unwrap();
       for (i, coordinator) in coordinators.iter_mut().enumerate() {