#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
const int N = 1010;
int n,a,b,c;
string s;

int main()
{
    int T;
    cin >> T;
    while(T--){
        cin >> n >> a >> b >> c;
        cin >> s;
        int cnt1 = 0,cnt2 = 0;
        for (int i = 0; i < n; i ++ ){
            if(s[i] == '0') cnt1++;
            else    cnt2++;
        }
        int res = 0;
        if(abs(a - b) > c){
            if(a > b)   res = cnt1 * c + (cnt1 + cnt2) * b;
            else    res = cnt2 * c + (cnt1 + cnt2) * a;
        }else   res = cnt1 * a + cnt2 * b;
        cout << res << endl;
    }
    return 0;
}