#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 7;
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  long long t;
  cin >> t;
  while (t--) {
    long long n;
    cin >> n;
    std::vector<long long> v(n);
    std::vector<string> ans(n + 1);
    long long tmp = 1, m = INT_MIN;
    for (long long i = 0; i < n; ++i) {
      cin >> v[i];
      m = max(m, v[i]);
    }
    for (long long i = 0; i <= m; ++i) ans[0] += 'a';
    for (long long i = 1; i <= n; ++i) {
      ans[i] = ans[i - 1];
      for (long long j = v[i - 1]; j <= m; ++j) {
        ans[i][j] = char('a' + tmp);
      }
      tmp++;
      tmp = tmp % 20;
    }
    for (long long i = 0; i < n + 1; ++i) cout << ans[i] << "\n";
  }
  return 0;
}
