#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n, a, b;
  string s;
  cin >> n >> a >> b >> s;
  long long x = b, y = 100000000000000000, tx, ty;
  for (int i = 0; i < n; i++) {
    if (s[i] == '0') {
      tx = min(x + a + b, y + 2 * a + b);
      ty = min(x + 2 * (a + b), y + a + 2 * b);
      x = tx, y = ty;
    } else {
      x = 100000000000000000;
      y += a + 2 * b;
    }
  }
  cout << x << endl;
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int t = 1;
  cin >> t;
  while (t--) solve();
}
