#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    long long n, a, b;
    cin >> n >> a >> b;
    string s;
    cin >> s;
    long long dp[n][2];
    dp[0][0] = dp[0][1] = a + b;
    for (int i = 1; i < n; i++) {
      if (s[i] == '0') {
        if (i > 1) {
          dp[i][0] = min(dp[i - 1][0] + a + b, dp[i - 1][1] + 2 * a + 2 * b);
          dp[i][1] = min(dp[i - 1][0] + 2 * a + b, dp[i - 1][1] + a + 2 * b);
        } else {
          dp[i][0] = dp[i - 1][0] + a + b;
          dp[i][1] = dp[i - 1][0] + 2 * a + b;
        }
      } else {
        if (i > 1)
          dp[i][1] =
              min(dp[i - 1][0] + 2 * a + 2 * b, dp[i - 1][1] + a + 2 * b);
        else
          dp[i][1] = dp[i - 1][0] + 2 * a + 2 * b;
        dp[i][0] = 1e16;
      }
    }
    cout << dp[n - 1][0] + b << endl;
  }
  return 0;
}
