#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 9;
const long double PI = 3.14159265358979;
long long binpow(long long x, long long y, long long p) {
  long long res = 1;
  x = x % p;
  if (x == 0) return 0;
  while (y > 0) {
    if (y & 1) res = (res * x) % p;
    y = y >> 1;
    x = (x * x) % p;
  }
  return res;
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
bool parity(long long x, long long y) {
  bool f = ((x ^ y) < 0);
  return !f;
}
string getBase(long long x, long long b) {
  string ans;
  while (x) {
    ans += ('0' + x % b);
    x /= b;
  }
  return ans;
}
void solve() {
  long long n;
  cin >> n;
  vector<long long> v(n + 1, 100);
  for (long long i = 1; i <= (n); i++) {
    cin >> v[i];
  }
  string s[105];
  for (long long i = 1; i <= (v[1]); i++) s[1] += 'a';
  for (int i = 2; i <= n; i++) {
    if (v[i - 1] <= v[i]) {
      for (long long j = 1; j <= (v[i - 1]); j++) s[i] += s[i - 1][j - 1];
      for (long long j = v[i - 1] + 1; j <= (v[i]); j++) s[i] += (i % 23 + 97);
    } else {
      for (long long j = 0; j <= (v[i - 1] - 1); j++) s[i] += s[i - 1][j];
    }
  }
  if (v[n] >= v[n - 1]) {
    s[n + 1] += s[n];
  } else {
    for (long long i = 1; i <= (v[n]); i++) s[n + 1] += s[n][i - 1];
  }
  for (long long i = 1; i <= (n + 1); i++) {
    if (i & 1)
      s[i] += 'y';
    else
      s[i] += 'z';
  }
  for (long long i = 1; i <= (n + 1); i++) cout << s[i] << '\n';
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int _;
  cin >> _;
  while (_--) solve();
  return 0;
}
