Fix test; take rest if balance too low.

Author: afck

linera-faucet/server/src/lib.rs

@@ -129,6 +129,7 @@ where
             .await
             .make_chain_client(self.main_chain_id)?;
         let maybe_tmp_chain_id = *self.tmp_chain_id.lock().await;
+        let main_balance = main_client.local_balance().await?;
         let tmp_chain_id = match maybe_tmp_chain_id {
             Some(tmp_chain_id) => tmp_chain_id,
             None => {
@@ -137,7 +138,8 @@ where
                     .amount
                     .try_add(MAX_FEE)?
                     .try_mul(u128::from(self.max_claims_per_chain))?
-                    .try_add(MAX_FEE)?; // One more block fee for closing the chain.
+                    .try_add(MAX_FEE)? // One more block fee for closing the chain.
+                    .min(main_balance.try_sub(MAX_FEE)?);
                 let ownership = main_client.chain_state_view().await?.ownership().clone();
                 let (message_id, certificate) = main_client
                     .open_chain(ownership, ApplicationPermissions::default(), balance)

linera-service/tests/linera_net_tests.rs

@@ -2861,8 +2861,9 @@ async fn test_end_to_end_faucet(config: impl LineraNetConfig) -> Result<()> {
     // Generate keys for client 2.
     let owner2 = client2.keygen().await?;
 
+    // We set the temporary chain limit to 1, so unused tokens remain on the main chain.
     let mut faucet_service = client1
-        .run_faucet(None, chain1, Amount::from_tokens(2), None)
+        .run_faucet(None, chain1, Amount::from_tokens(2), Some(1))
         .await?;
     let faucet = faucet_service.instance();
     let outcome = faucet.claim(&owner2).await?;