#include <bits/stdc++.h>
using namespace std;
int main() {
  int t;
  cin >> t;
  while (t--) {
    string s;
    int n, m, z, i, j, k, l, r, x, y, bugi = 0, chigi = 0, moga = 0;
    cin >> n;
    s = string(100, 'a');
    for (i = 0; i < n; i++) {
      cin >> x;
      if (i == 0) cout << s << endl;
      if (s[x] < 'z')
        s[x]++;
      else
        s[x]--;
      cout << s << endl;
    }
  }
  return 0;
}
