Compute Commitment Hash (#1709)

* compute commitment hash

* test

Author: claravanstaden

contracts/src/BeefyClient.sol

@@ -465,6 +465,14 @@ contract BeefyClient {
         return Bitfield.createBitfield(bitsToSet, length);
     }
 
+    /**
+     * @dev Compute the hash of a commitment
+     * @param commitment the commitment to hash
+     */
+    function computeCommitmentHash(Commitment calldata commitment) external pure returns (bytes32) {
+        return keccak256(encodeCommitment(commitment));
+    }
+
     /**
      * @dev Helper to create a final bitfield, with subsampled validator selections
      * @param commitmentHash contains the commitmentHash signed by the validators

contracts/test/BeefyClient.t.sol

@@ -879,4 +879,11 @@ contract BeefyClientTest is Test {
             commitment, bitfield, fiatShamirValidatorProofs, mmrLeaf, mmrLeafProofs, leafProofOrder
         );
     }
+
+    function testComputeCommitmentHash() public {
+        BeefyClient.Commitment memory commitment = initialize(setId);
+        bytes32 computedHash = beefyClient.computeCommitmentHash(commitment);
+        // commitHash is loaded from the test data file and should match
+        assertEq(computedHash, commitHash);
+    }
 }