#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long int t;
  cin >> t;
  while (t--) {
    long long int n;
    cin >> n;
    long long int a[n];
    for (long long int i = 0; i < n; i++) {
      cin >> a[i];
    }
    vector<string> ans;
    string tem;
    for (long long int i = 0; i < 50; i++) tem += 'a';
    ans.push_back(tem);
    for (long long int i = 0; i < n; i++) {
      string tem2;
      for (long long int j = 0; j < 50; j++) {
        if (j < a[i]) {
          tem2 += tem[j];
        } else {
          char ch;
          if (tem[j] + 1 <= 'z') {
            ch = ++tem[j];
          } else
            ch = --tem[j];
          tem2 += ch;
        }
      }
      ans.push_back(tem2);
      tem = tem2;
    }
    for (string str : ans) {
      cout << str << "\n";
    }
  }
}
