#include <bits/stdc++.h>
using namespace std;
int64_t R = 1;
void solution() {
  int64_t n, mx = 0;
  string s =
      "abcdefghijklmnopqrstuvwxabcdefghijklmnopqrstuvwxabcdefghijklmnopqrstuvwx"
      "abcdefghijklmnopqrstuvwxabcdefghijklmnopqrstuvwxabcdefghijklmnopqrstuvw"
      "x";
  cin >> n;
  int64_t a[n];
  for (int i = 0; i < n; i++) {
    cin >> a[i];
    mx = max(mx, a[i]);
  }
  string str;
  for (int i = 0; i < mx; i++) {
    str += s[i];
  }
  if (mx == 0) {
    str = 'z';
    mx = 1;
  }
  cout << str << endl;
  for (int i = 0; i < n; i++) {
    for (int j = a[i]; j < mx; j++) {
      if (str[j] == 'z') {
        str[j] = 'y';
      } else {
        str[j] = 'z';
      }
    }
    cout << str << endl;
  }
}
int main() {
  cin >> R;
  while (R--) {
    solution();
  }
  return 0;
}
