Add minimal permissions test

src/common/Permission.sol

@@ -60,13 +60,13 @@ contract Permission is IPermission {
      *  @param _roleBits The bits representing the permissions to check.
      *  @param _startIndex The start index of the range. (inclusive)
      *  @param _endIndex The end index of the range. (non-inclusive)
-     *  @return hodlers The holders with the given permissions, within the given range.
+     *  @return holders The holders with the given permissions, within the given range.
      */
-    function getRoleMembers(uint256 _roleBits, uint256 _startIndex, uint256 _endIndex) external view returns (address[] memory hodlers) {
+    function getRoleMembers(uint256 _roleBits, uint256 _startIndex, uint256 _endIndex) external view returns (address[] memory holders) {
         PermissionStorage.Data storage data = PermissionStorage.data();
 
         uint256 len = data.roleMemberCount;
-        if(_endIndex >= _startIndex || _endIndex > len) {
+        if(_startIndex >= _endIndex || _endIndex > len) {
             revert PermissionInvalidRange();
         }
 
@@ -77,14 +77,14 @@ contract Permission is IPermission {
             }
         }
 
-        hodlers = new address[](count);
+        holders = new address[](count);
         uint256 idx = 0; 
 
-        for (uint256 j = 0; j < len; j++) {
+        for (uint256 j = 1; j < len + 1; j++) {
             address holder = data.memberAtIndex[j];
 
             if (hasRole(holder, _roleBits)) {
-                hodlers[idx] = holder;
+                holders[idx] = holder;
                 idx++;
             }
         }

test/common/Permission.t.sol

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity ^0.8.0;
+
+import { Test } from "forge-std/Test.sol";
+import { Permission } from "src/common/Permission.sol";
+
+contract PermissionExample is Permission {
+
+    constructor(address _admin) {
+        _setupRole(_admin, ADMIN_ROLE_BITS);
+    }
+}
+
+contract PermissionTest is Test {
+
+    PermissionExample permission;
+    address public admin = address(0x123);
+
+    uint256 public permissionBitsOne = 2 ** 2;
+    uint256 public permissionBitsTwo = 2 ** 3;
+    uint256 public permissionBitsThree = 2 ** 4;
+
+    mapping(address => bool) public setRole;
+
+    function setUp() public {
+        permission = new PermissionExample(admin);
+    }
+
+    function test_roles() public {
+
+        uint256 count = 100;
+
+        for (uint256 i = 1; i <= count; i++) {
+            address account = address(uint160(i));
+
+            vm.startPrank(admin);
+
+            permission.grantRole(account, permissionBitsOne);
+            permission.grantRole(account, permissionBitsTwo);
+            permission.grantRole(account, permissionBitsThree);
+
+            vm.stopPrank();
+
+            setRole[account] = true;
+
+            assert(permission.hasRole(account, permissionBitsOne | permissionBitsTwo | permissionBitsThree));
+        }
+
+        address[] memory accounts = permission.getRoleMembers(permissionBitsOne | permissionBitsTwo | permissionBitsThree, 0, permission.getRoleMemberCount());
+        assertEq(accounts.length, 100);
+
+        for(uint256 i = 0; i < accounts.length; i++) {
+            assert(setRole[accounts[i]]);
+        }
+
+        for (uint256 i = 25; i <= 74; i++) {
+            address account = address(uint160(i));
+
+            vm.startPrank(admin);
+
+            permission.revokeRole(account, permissionBitsOne);
+            permission.revokeRole(account, permissionBitsTwo);
+            permission.revokeRole(account, permissionBitsThree);
+
+            vm.stopPrank();
+
+            setRole[account] = false;
+
+            assert(!permission.hasRole(account, permissionBitsOne | permissionBitsTwo | permissionBitsThree));
+        }
+
+        address[] memory accountsAfter = permission.getRoleMembers(permissionBitsOne | permissionBitsTwo | permissionBitsThree, 0, permission.getRoleMemberCount());
+        assertEq(accountsAfter.length, 50);
+    }
+}