#include <bits/stdc++.h>
using namespace std;
long long t, n, a, b;
char s[200005];
long long k[200005];
int main() {
  cin >> t;
  while (t--) {
    cin >> n >> a >> b;
    cin >> s;
    long long m = 0;
    k[m] = -1;
    m++;
    long long suml = 0, sums = 0, sumz = 0, sump = n + 1;
    for (int i = 0; i < strlen(s); i++) {
      if (s[i] == '0' && i + 1 < strlen(s) && s[i + 1] == '1') {
        sump += 2;
      }
      if (s[i] == '1' && i + 1 < strlen(s) && s[i + 1] == '1') {
        sump++;
      }
      if (s[i] == '1')
        if (s[i] == '1' && i + 1 < strlen(s) && s[i + 1] == '0') {
          k[m] = i + 1;
          m++;
          sumz++;
        }
      if (s[i] == '0' && i + 1 < strlen(s) && s[i + 1] == '1') {
        k[m] = i;
        m++;
        sumz++;
      }
    }
    k[m] = n;
    m++;
    for (int i = 2; i < m - 2; i += 2) {
      if (2 * a >= (k[i + 1] - k[i]) * b) {
        sumz -= 2;
        sump += k[i + 1] - k[i];
      }
    }
    cout << sump * b + sumz * 2 * a + (n - sumz) * a << endl;
  }
}
