#include <bits/stdc++.h>
using namespace std;
inline void print(vector<int> &v) {
  for (int i : v) cout << i << " ";
  cout << "\n";
}
inline void print(vector<long long> &v) {
  for (long long i : v) cout << i << " ";
  cout << "\n";
}
inline void print(vector<vector<int> > &v) {
  for (vector<int> i : v) print(i);
}
inline void print(pair<int, int> p) {
  cout << "(" << p.first << ":" << p.second << "), ";
}
inline void print(vector<pair<int, int> > &P) {
  for (pair<int, int> i : P) print(i);
  cout << "\n";
}
inline void print(set<int> &s) {
  for (int i : s) cout << i << " ";
  cout << "\n";
}
inline void print(map<int, int> &m) {
  for (auto i : m) print(i);
  cout << "\n";
}
inline void srt(vector<long long> &v) { sort(v.begin(), v.end()); }
long long power(long long a, long long b, long long MOD) {
  long long res = 1;
  while (b) {
    if (b % 2) res = (res * a) % MOD;
    a = (a * a) % MOD;
    b /= 2;
  }
  return res;
}
long long iMOD(long long a, long long p) { return power(a, p - 2, p); }
bool compare(int a, int b) { return a > b; }
inline void srtc(vector<long long> &v) { sort(v.begin(), v.end(), compare); }
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int T = 1;
  cin >> T;
  while (T--) {
    long long int n;
    cin >> n;
    unsigned long long int sum = 0, sumxor = 0;
    for (int i = 0; i < n; i++) {
      long long int y;
      cin >> y;
      sum += y;
      sumxor = (sumxor ^ y);
    }
    if (sum == (2 * sumxor)) {
      cout << "0"
           << "\n";
    } else {
      cout << "2"
           << "\n";
      cout << sumxor << " " << sum + sumxor;
    }
    cout << "\n";
  }
  return 0;
}
