#include<iostream>
using namespace std;

int main() {
    int T = 1;
    cin >> T;
    while(T--) {
        int n, a, b, c;
        cin >> n >> a >> b >> c;

        string s;
        cin >> s;

        int ret = 0;

        if(abs(a - b) > c) {
            if(a < b) {
                for(int i = 0; i < n; i++) {
                    if(s[i] == '0') ret += a;
                    else ret += a + c;
                }
            } else {
                for(int i = 0; i < n; i++) {
                    if(s[i] == '1') ret += b;
                    else ret += b + c;
                }
            }
        } else {
            for(int i = 0; i < n; i++) {
                if(s[i] == '0') ret += a;
                else ret += b;
            }
        }
        cout << ret << endl;
    }
    return 0;
}