Refactor setting unborn channel signer unavailability

For opening and accepting a channel, to test an asynchronous per
commitment point call, we need to set the test signer to return Err(())
for a channel signer that hasn't been created until the middle of the
create_channel or handle_open_channel call. To do this, we simply just
push a mask to a queue in the keys manager, and the next channel signer
it creates, it'll set that mask to be unavailable.

Author: alecchendev

lightning/src/ln/functional_test_utils.rs

@@ -558,6 +558,11 @@ impl<'a, 'b, 'c> Node<'a, 'b, 'c> {
 			});
 		}
 	}
+
+	#[cfg(test)]
+	pub fn set_unborn_channel_signer_ops_unavailable(&self, mask: u32) {
+		self.keys_manager.unavailable_signers.lock().unwrap().push_back(mask);
+	}
 }
 
 /// If we need an unsafe pointer to a `Node` (ie to reference it in a thread

lightning/src/util/test_utils.rs

@@ -1214,7 +1214,7 @@ pub struct TestKeysInterface {
 	pub disable_revocation_policy_check: bool,
 	enforcement_states: Mutex<HashMap<[u8;32], Arc<Mutex<EnforcementState>>>>,
 	expectations: Mutex<Option<VecDeque<OnGetShutdownScriptpubkey>>>,
-	pub unavailable_signers: Mutex<HashSet<[u8; 32]>>,
+	pub unavailable_signers: Mutex<VecDeque<u32>>,
 }
 
 impl EntropySource for TestKeysInterface {
@@ -1274,8 +1274,9 @@ impl SignerProvider for TestKeysInterface {
 		let keys = self.backing.derive_channel_signer(channel_value_satoshis, channel_keys_id);
 		let state = self.make_enforcement_state_cell(keys.commitment_seed);
 		let signer = TestChannelSigner::new_with_revoked(keys, state, self.disable_revocation_policy_check);
-		if self.unavailable_signers.lock().unwrap().contains(&channel_keys_id) {
-			signer.set_available(false);
+		#[cfg(test)]
+		if let Some(mask) = self.unavailable_signers.lock().unwrap().pop_front() {
+			signer.set_ops_available(mask, false)
 		}
 		signer
 	}
@@ -1315,7 +1316,7 @@ impl TestKeysInterface {
 			disable_revocation_policy_check: false,
 			enforcement_states: Mutex::new(new_hash_map()),
 			expectations: Mutex::new(None),
-			unavailable_signers: Mutex::new(new_hash_set()),
+			unavailable_signers: Mutex::new(VecDeque::new()),
 		}
 	}