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

void mainSolve()
{
  int n;
  cin >> n;
  vector<int> B(n + 1, 0);
  for (int i = 1; i <= n; i++)
    cin >> B[i];
  int maxi = -1;
  for (int i = 1; i <= n; i++)
  {
    if (B[i] >= 0)
    {
      if (B[i] == maxi)
        B[i] = -1;
      else
      {
        if (maxi > B[i])
        {
          cout << -1 << '\n';
          return;
        }
        maxi = B[i];
      }
    }
  }
  vector<int> A(n + 1, -1);
  set <int> slots;
  for (int i = 1; i <= n + 10; i++)
  {
    slots.insert(i);
  }
  set <int> elements;
  for (int i = 0; i <= n + 10; i++)
    elements.insert(i);
  for (int i = 1; i <= n; i++)
  {
    if (B[i] >= 0)
      elements.erase(B[i]);
  }
  bool first_time = true;
  maxi = -1;
  for (int i = 1; i <= n; i++)
  {
    if (B[i] == -1)
      continue;
    if (!first_time)
    {
      A[i] = maxi;
      slots.erase(i);
    }
    else
      first_time = false;
    while (true)
    {
      auto it = elements.begin();
      if ((*it) >= B[i])
        break;
      int l = (*slots.begin());
      if (l > i)
      {
        cout << -1 << '\n';
        return;
      }
      A[l] = (*it);
      slots.erase(l);
      elements.erase(it);
    }
    maxi = B[i];
  }
  for (int i = 1; i <= n; i++)
  {
    if (A[i] == -1)
      A[i] = n + 5;
  }
  for (int i = 1; i <= n; i++)
    cout << A[i] << ' ';
  cout << '\n';
}

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