#include <bits/stdc++.h>
using namespace std;
const int N = 1010;

int n, a[N];

int MEX() {
    int cnt[n + 1] = {};
    for (int i = 0; i < n; i++)
        ++cnt[a[i]];
    for (int i = 0; i <= n; i++)
        if (cnt[i] == 0) return i;
}

void solve() {
    cin >> n;
    for (int i = 0; i < n; i++)
        cin >> a[i];
    vector<int> res;
    while (!is_sorted(a, a + n)) {
        int mex = MEX();
        if (mex == n) {
            for (int i = 0; i < n; i++) {
                if (a[i] != i) {
                    a[i] = n;
                    res.push_back(i);
                    break;
                }
            }
        } else {
            a[mex] = mex;
            res.push_back(mex);
        }
    }
    cout << res.size() << "\n";
    for (auto i : res) cout << i + 1 << ‘ ‘;
    cout << "\n";
}

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