diff --git a/foundry.lock b/foundry.lock
new file mode 100644
index 0000000..13ce27d
--- /dev/null
+++ b/foundry.lock
@@ -0,0 +1,8 @@
+{
+  "lib/forge-std": {
+    "rev": "e4aef94c1768803a16fe19f7ce8b65defd027cfd"
+  },
+  "lib/openzeppelin-contracts": {
+    "rev": "cb2aaaa04a292887c49839cd958b08a83979d746"
+  }
+}
\ No newline at end of file
diff --git a/foundry.toml b/foundry.toml
index 0ec2c24..cdc0038 100644
--- a/foundry.toml
+++ b/foundry.toml
@@ -5,5 +5,6 @@ libs = ['lib']
 fuzz_runs=5000
 fuzz.max_test_rejects=500000
 fs_permissions = [{ access = "read-write", path = "./"}]
+ffi = true
 
 # See more config options https://github.com/gakonst/foundry/tree/master/config
\ No newline at end of file
diff --git a/src/common/MurkyBase.sol b/src/common/MurkyBase.sol
index d9344e9..6a6a491 100644
--- a/src/common/MurkyBase.sol
+++ b/src/common/MurkyBase.sol
@@ -2,6 +2,8 @@
 pragma solidity ^0.8.4;
 
 abstract contract MurkyBase {
+    /// @dev Thrown when trying to generate a root or proof for a single leaf array
+    error SingleLeaf();
     /**
      *
      * CONSTRUCTOR *
@@ -21,7 +23,7 @@ abstract contract MurkyBase {
      * PROOF VERIFICATION *
      *
      */
-    function verifyProof(bytes32 root, bytes32[] memory proof, bytes32 valueToProve)
+    function verifyProof(bytes32 root, bytes32[] calldata proof, bytes32 valueToProve)
         external
         pure
         virtual
@@ -44,7 +46,7 @@ abstract contract MurkyBase {
      *
      */
     function getRoot(bytes32[] memory data) public pure virtual returns (bytes32) {
-        require(data.length > 1, "won't generate root for single leaf");
+        if (data.length <= 1) revert SingleLeaf();
         while (data.length > 1) {
             data = hashLevel(data);
         }
@@ -52,7 +54,7 @@ abstract contract MurkyBase {
     }
 
     function getProof(bytes32[] memory data, uint256 node) public pure virtual returns (bytes32[] memory) {
-        require(data.length > 1, "won't generate proof for single leaf");
+        if (data.length <= 1) revert SingleLeaf();
         // The size of the proof is equal to the ceiling of log2(numLeaves)
         bytes32[] memory result = new bytes32[](log2ceilBitMagic(data.length));
         uint256 pos = 0;
diff --git a/src/test/Merkle.t.sol b/src/test/Merkle.t.sol
index 252a1f6..9d2083a 100644
--- a/src/test/Merkle.t.sol
+++ b/src/test/Merkle.t.sol
@@ -2,6 +2,7 @@
 pragma solidity ^0.8.4;
 
 import "../Merkle.sol";
+import "../common/MurkyBase.sol";
 import "forge-std/Test.sol";
 import "openzeppelin-contracts/contracts/utils/cryptography/MerkleProof.sol";
 
@@ -68,14 +69,14 @@ contract ContractTest is Test {
     function testWontGetRootSingleLeaf() public {
         bytes32[] memory data = new bytes32[](1);
         data[0] = bytes32(0x0);
-        vm.expectRevert("won't generate root for single leaf");
+        vm.expectRevert(MurkyBase.SingleLeaf.selector);
         m.getRoot(data);
     }
 
     function testWontGetProofSingleLeaf() public {
         bytes32[] memory data = new bytes32[](1);
         data[0] = bytes32(0x0);
-        vm.expectRevert("won't generate proof for single leaf");
+        vm.expectRevert(MurkyBase.SingleLeaf.selector);
         m.getProof(data, 0x0);
     }
 
diff --git a/src/test/Xorkle.t.sol b/src/test/Xorkle.t.sol
index 6137817..b42c871 100644
--- a/src/test/Xorkle.t.sol
+++ b/src/test/Xorkle.t.sol
@@ -2,6 +2,7 @@
 pragma solidity ^0.8.4;
 
 import "../Xorkle.sol";
+import "../common/MurkyBase.sol";
 import "forge-std/Test.sol";
 
 contract ContractTest is Test {
@@ -52,14 +53,14 @@ contract ContractTest is Test {
     function testWontGetRootSingleLeaf() public {
         bytes32[] memory data = new bytes32[](1);
         data[0] = bytes32(0x0);
-        vm.expectRevert("won't generate root for single leaf");
+        vm.expectRevert(MurkyBase.SingleLeaf.selector);
         m.getRoot(data);
     }
 
     function testWontGetProofSingleLeaf() public {
         bytes32[] memory data = new bytes32[](1);
         data[0] = bytes32(0x0);
-        vm.expectRevert("won't generate proof for single leaf");
+        vm.expectRevert(MurkyBase.SingleLeaf.selector);
         m.getProof(data, 0x0);
     }