DiamondTest.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

import "forge-std/Test.sol";
import "solady/utils/LibString.sol";

abstract contract DiamondTest is Test {
    using LibString for string;

    function _facetSelectors(
        string memory facetName
    ) internal returns (bytes4[] memory selectors) {
        string[] memory output = string(
            vm.ffi(
                string(
                    abi.encodePacked("forge inspect ", facetName, " methods")
                ).split(" ")
            )
        ).split(":");

        uint256 count = output.length - 1;
        string memory part;
        uint256 end;
        uint256 start;

        unchecked {
            selectors = new bytes4[](count);

            for (uint256 i = 0; i < count; ++i) {
                part = output[i];
                start = part.indexOf('  "', 0) + 3;
                end = part.indexOf('"', start);
                selectors[i] = bytes4(keccak256(bytes(part.slice(start, end))));
            }
        }
    }
}