How to return whole mapping in solidity

MappingTest.sol

pragma solidity ^0.4.25;

contract MappingTest {
    mapping(uint=>address) public addresses;
    uint addressRegistryCount;

    function set(address userAddress) public{
        addresses[addressRegistryCount] = userAddress;
        addressRegistryCount++;
    }

    function getAll() public view returns (address[] memory){
        address[] memory ret = new address[](addressRegistryCount);
        for (uint i = 0; i < addressRegistryCount; i++) {
            ret[i] = addresses[i];
        }
        return ret;
    }
}