#include <bits/stdc++.h>
using namespace std;
void print() { cout << '\n'; }
template <typename T, typename... Types>
void print(T var1, Types... var2) {
  cout << var1 << ' ';
  print(var2...);
}
template <typename T>
void print(vector<T> &var1) {
  for (auto &i : var1) cout << i << ' ';
  cout << '\n';
}
template <typename T>
void print(T start, T end) {
  for (; start != end; start++) cout << *start << ' ';
  cout << '\n';
}
template <typename T>
void print(pair<T, T> &var1) {
  cout << var1.first << ' ' << var1.second << ' ';
  cout << '\n';
}
template <typename T>
void read(T &x) {
  cin >> x;
}
template <typename T, typename... Types>
void read(T &var1, Types &...var2) {
  cin >> var1;
  read(var2...);
}
template <typename T>
void read(vector<T> &var1) {
  for (auto &i : var1) read(i);
}
template <typename T>
void read(T start, T end) {
  for (; start != end; start++) cin >> *start;
}
template <typename T>
void read(pair<T, T> &var1) {
  cin >> var1.first >> var1.second;
}
template <typename T>
T Max(T x) {
  return x;
}
template <typename T, typename... Types>
T Max(T var1, Types... var2) {
  return var1 >= Max(var2...) ? var1 : Max(var2...);
}
template <typename T>
T Min(T x) {
  return x;
}
template <typename T, typename... Types>
T Min(T var1, Types... var2) {
  return var1 <= Min(var2...) ? var1 : Min(var2...);
}
long long INF = 1000000000000000005LL;
void solve();
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int t = 1;
  cin >> t;
  while (t--) {
    solve();
  }
  cerr << "time taken : " << (float)clock() / CLOCKS_PER_SEC << " secs" << endl;
  return 0;
}
void solve() {
  long long n;
  cin >> n;
  vector<long long> a(n);
  for (long long i = 0; i < n; i++) cin >> a[i];
  char c1 = 'a';
  char c2 = 'b';
  string s = "";
  s = "a";
  for (long long i = 0; i < 51; i++) {
    s += 'a';
  }
  cout << s << '\n';
  for (long long i = 0; i < n; i++) {
    string ss = "";
    long long j = 0;
    while (j < a[i]) {
      ss += s[j];
      j++;
    }
    if (s[j] == 'a') {
      while (j < 51) {
        ss += 'b';
        j++;
      }
    } else {
      while (j < 51) {
        ss += 'a';
        j++;
      }
    }
    s = ss;
    cout << ss << '\n';
  }
}
