#include <bits/stdc++.h>
using namespace std;
void solve() {
  int n;
  cin >> n;
  vector<int> sizes(n);
  int max_size = 0;
  for (int i = 0; i < n; ++i) {
    cin >> sizes[i];
    if (max_size < sizes[i]) max_size = sizes[i];
  }
  string somestr(max_size + 1, 'a');
  cout << somestr << endl;
  for (int i = 0; i < n; ++i) {
    somestr[sizes[i]]++;
    if (somestr[sizes[i]] == 'z') somestr[sizes[i]] = 'a';
    cout << somestr << endl;
  }
}
int main() {
  int t;
  cin >> t;
  while (t--) solve();
}
