#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t;
  cin >> t;
  while (t--) {
    long long int n;
    cin >> n;
    long long int a[n + 1];
    for (long long int i = 1; i <= n; i++) {
      cin >> a[i];
    }
    string arr[n + 1];
    for (long long int i = 0; i <= 52; i++) {
      arr[0] = arr[0] + 'a';
    }
    for (long long int i = 1; i <= n; i++) {
      long long int j;
      for (j = 0; j < a[i]; j++) {
        arr[i] += arr[i - 1][j];
      }
      if (arr[i - 1][j] == 'b') {
        for (; j <= 52; j++) arr[i] += 'a';
      } else {
        for (; j <= 52; j++) arr[i] += 'b';
      }
    }
    for (long long int i = 0; i <= n; i++) {
      cout << arr[i] << "\n";
    }
  }
  return 0;
}
