#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> arr(n);
    map<int, int> mp;
    for (int i = 0; i < n; i++) {
      cin >> arr[i];
      mp[arr[i]]++;
    }
    int ans = 0;
    int ct = 0;
    for (int i = 0; i <= 100; i++) {
      if (ct < 2) {
        if (mp[i] == 0) {
          ans += (2 - ct) * i;
          if (ct == 1)
            ct++;
          else
            ct += 2;
        } else if (mp[i] % 2 == 0)
          continue;
        else if (mp[i] == 1) {
          if (ct == 1)
            continue;
          else {
            ct++;
            ans += i;
          }
        }
      } else
        break;
    }
    cout << ans << endl;
  }
}
