#include <bits/stdc++.h>
using namespace std;
const long long int inf = 1e15;
const int M = 1e9 + 7;
long long int arr[5000000];
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long int T, n;
  cin >> T;
  while (T--) {
    long long int max_len = 0;
    cin >> n;
    for (int i = 0; i < n; ++i) {
      cin >> arr[i];
      max_len = max(arr[i], max_len);
    }
    vector<string> ans;
    string str(max_len + 2, 'a');
    string b = str;
    ans.emplace_back(str);
    for (int i = 0; i < n; ++i) {
      if (str[arr[i]] == 'a')
        b[arr[i]] = 'b';
      else
        b[arr[i]] = 'a';
      ans.emplace_back(b);
      str = b;
    }
    for (auto i : ans) cout << i << endl;
  }
  return 0;
}
