EVM/Add setter and tests for per-chain thresholds

evm/src/NttManager/ManagerBase.sol

@@ -443,6 +443,21 @@ abstract contract ManagerBase is
 
  emit ThresholdChanged(oldThreshold, threshold);
  }
+
+ /// @inheritdoc IManagerBase
+ function setThresholdPerChain(uint16 forChainId, uint8 threshold) external onlyOwner {
+ if (threshold == 0) {
+ revert ZeroThreshold();
+ }
+
+ mapping(uint16 => _Threshold) storage _threshold = _getThresholdStoragePerChain();
+ uint8 oldThreshold = _threshold[forChainId].num;
+
+ _threshold[forChainId].num = threshold;
+ _checkThresholdInvariants(_threshold[forChainId].num);
+
+ emit PerChainThresholdChanged(forChainId, oldThreshold, threshold);
+ }
 
  // =============== Internal ==============================================================
 
@@ -515,7 +530,10 @@ abstract contract ManagerBase is
  }
 
  function _checkThresholdInvariants() internal view {
- uint8 threshold = _getThresholdStorage().num;
+ _checkThresholdInvariants(_getThresholdStorage().num);
+ }
+
+ function _checkThresholdInvariants(uint8 threshold) internal pure {
  _NumTransceivers memory numTransceivers = _getNumTransceiversStorage();
 
  // invariant: threshold <= enabledTransceivers.length

evm/src/interfaces/IManagerBase.sol

@@ -48,6 +48,14 @@ interface IManagerBase {
  /// @param oldThreshold The old threshold.
  /// @param threshold The new threshold.
  event ThresholdChanged(uint8 oldThreshold, uint8 threshold);
+
+ /// @notice Emmitted when the per-chain threshold required transceivers is changed.
+ /// @dev Topic0
+ /// 0x2a855b929b9a53c6fb5b5ed248b27e502b709c088e036a5aa17620c8fc5085a9.
+ /// @param chainId The chain to which the threshold applies
+ /// @param oldThreshold The old threshold.
+ /// @param threshold The new threshold.
+ event PerChainThresholdChanged(uint16 chainId, uint8 oldThreshold, uint8 threshold);
 
  /// @notice Emitted when an transceiver is removed from the nttManager.
  /// @dev Topic0
@@ -128,6 +136,16 @@ interface IManagerBase {
  function setThreshold(
  uint8 threshold
  ) external;
+
+ /// @notice Sets the per-chain threshold for the number of attestations required for a message
+ /// to be considered valid. Note that if a threshold is not specified for a chain, the default applies.
+ /// @param chainId The chain for which the threshold applies
+ /// @param threshold The new threshold.
+ /// @dev This method can only be executed by the `owner`.
+ function setThresholdPerChain(
+ uint16 chainId,
+ uint8 threshold
+ ) external;
 
  /// @notice Sets the transceiver for the given chain.
  /// @param transceiver The address of the transceiver.