#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  int n, c0, c1, h;
  string s;
  while (t != 0) {
    cin >> n >> c0 >> c1 >> h >> s;
    int maxC = max(c0, c1), minC = min(c0, c1);
    int value = minC * n;
    int cnt = 0;
    for (int i = 0; i < n; i++)
      if (s[i] == '1') cnt++;
    if (maxC - minC > h) {
      if (maxC == c1)
        value += h * cnt;
      else
        value += h * (n - cnt);
    } else {
      if (maxC == c1)
        value += (maxC - minC) * cnt;
      else
        value += (maxC - minC) * (n - cnt);
    }
    cout << value << endl;
    t--;
  }
  return 0;
}
