#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1 + 2e5;
const long long inf = 1e18;
string s;
long long n, f[MAXN][2], a, b, t;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> t;
  while (t--) {
    cin >> n >> a >> b >> s;
    s = ' ' + s;
    f[0][0] = b;
    f[0][1] = inf;
    for (int i = 1; i <= n; ++i) {
      if (s[i] == '0') {
        f[i][1] = min(f[i - 1][1] + a + 2 * b, f[i - 1][0] + 2 * (a + b));
        f[i][0] = min(f[i - 1][1] + 2 * a + b, f[i - 1][0] + a + b);
      } else {
        f[i][1] = f[i - 1][1] + 2 * b + a;
        f[i][0] = inf;
      }
    }
    cout << f[n][0] << '\n';
  }
  return 0;
}
