#include <bits/stdc++.h>
using namespace std;
bool a[210] = {0};
bool testcase = 1;
void SieveOfEratosthenes() {
  long long n = 200;
  memset(a, true, 210);
  for (long long p = 2; p * p <= n; p++) {
    if (a[p] == true) {
      for (long long i = p * p; i <= n; i += p) a[i] = false;
    }
  }
}
long long gcd(long long a, long long b) {
  if (a == 0) return b;
  return gcd(b % a, a);
}
void solve() {
  long long n, c0, c1, h;
  cin >> n >> c0 >> c1 >> h;
  string s;
  cin >> s;
  long long on = 0, ze = 0;
  for (long long i = 0; i < n; i++) {
    if (s[i] == '0')
      ze++;
    else
      on++;
  }
  long long c = 0;
  if (c0 + h < c1) {
    ze = ze + on;
    c = on;
    on = 0;
  } else if (c1 + h < c0) {
    on = on + ze;
    c = ze;
    ze = 0;
  }
  cout << ((c1 * on) + (c0 * ze) + (c * h));
}
int32_t main() {
  std::ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
  long long k;
  if (testcase) {
    cin >> k;
  } else
    k = 1;
  while (k--) {
    solve();
    cout << endl;
  }
  return 0;
}
