#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long int i, n, t, j = 0, p, x, l = 0, r = 0, y, k, c, sum = 0, m, d,
                         cnts = 0;
  cin >> t;
  while (t--) {
    cin >> n;
    vector<long long int> a(n);
    p = 0;
    for (i = 0; i < n; i++) {
      cin >> a[i];
      p = max(p, a[i]);
    }
    string s;
    for (i = 0; i < 60; i++) {
      s += 97;
    }
    cout << s << endl;
    for (i = 0; i < n; i++) {
      p = a[i];
      for (j = 0; j < 60; j++) {
        p--;
        if (p < 0) {
          l = (s[j] + 1);
          if (l > 122) {
            l = 97;
          }
          s[j] = l;
        }
      }
      cout << s << endl;
    }
  }
}
