#include <bits/stdc++.h>
using namespace std;
void solve() {
  long long n, a, b, dp[200005][2];
  cin >> n >> a >> b;
  string t;
  cin >> t;
  memset(dp, 0x3f, sizeof(dp));
  dp[0][0] = b;
  for (int i = 0; i < n; i++) {
    if (t[i] == '1')
      dp[i + 1][1] = dp[i][1] + a + 2 * b;
    else {
      dp[i + 1][0] = min(dp[i][0] + a + b, dp[i][1] + 2 * a + b);
      dp[i + 1][1] = min(dp[i][0] + 2 * (a + b), dp[i][1] + a + 2 * b);
    }
  }
  cout << dp[n][0] << endl;
}
int main() {
  int t;
  scanf("%d", &t);
  while (t--) solve();
  return 0;
}
