#include <bits/stdc++.h>   using namespace std;   int main() {     int t;     cin >> t;     while (t--) {       int n, c1, c2, h;       cin >> n >> c1 >> c2 >> h;       int zero = 0, one = 0;       int cost = 0;       for (int i = 0; i < n; i++) {         char ch;         cin >> ch;         if (ch ==  0 )           cost += min(h + c2, c1);         else           cost += min(h + c1, c2);       }       cout << cost << endl;     }   }   