AccessManager tests consolidation (#4655)

test/helpers/namespaced-storage.js

@@ -0,0 +1,30 @@
+const { artifacts } = require('hardhat');
+
+function namespaceId(contractName) {
+  return `openzeppelin.storage.${contractName}`;
+}
+
+function namespaceLocation(id) {
+  const hashIdBN = web3.utils.toBN(web3.utils.keccak256(id)).subn(1); // keccak256(id) - 1
+  const hashIdHex = web3.utils.padLeft(web3.utils.numberToHex(hashIdBN), 64);
+
+  const mask = BigInt(web3.utils.padLeft('0x00', 64, 'f')); // ~0xff
+
+  return BigInt(web3.utils.keccak256(hashIdHex)) & mask;
+}
+
+function namespaceSlot(contractName, offset) {
+  try {
+    // Try to get the artifact paths, will throw if it doesn't exist
+    artifacts._getArtifactPathSync(`${contractName}Upgradeable`);
+    return offset + namespaceLocation(namespaceId(contractName));
+  } catch (_) {
+    return offset;
+  }
+}
+
+module.exports = {
+  namespaceSlot,
+  namespaceLocation,
+  namespaceId,
+};