#include <bits/stdc++.h>
using namespace std;

int n;

void solve(){
    cin >> n;
    int x;
    int sum = 0, b = 0;
    int ttl1 = 0, ttl0 = 0, ttlm1 = 0;
    for(int i = 0; i < n; i++){
        cin >> x;
        
        if(x == 1) ttl1++;
        if(x == -1) ttlm1++;
        if(x == 0) ttl0++;

        if(x == -1) sum--;
        else sum++;

        if(sum < 0) b = 1;
    }

    if(b == 1){
        cout << -1 << "\n";
        return;
    }
    
    int ttl = ttl0 + ttlm1 - ttl1;
    if(ttl % 2 == 0) ttl = ttl / 2;
    else ttl = ttl / 2 + 1;

    ttl1 += ttl;
    ttlm1 += (ttl0 - ttl);
    
    int s1 = ttl1 + 1;
    int s2 = s1 - ttlm1;
    
    if(s1 == 0 && s2 == 0) {
        cout << "-1\n";
        return;
    }
    cout << 1 / 0 << '\n';
    return;
    int a = __gcd(abs(s1), abs(s2));
    assert(a != 0);
    cout << s1 / a << " " << s2 / a << "\n";
}

int main(){
    int t; 
    cin >> t;
    while(t--){
        solve();
    }
    return 0;
}