source_code: // package contest;
  
  import java.io.*;
  import java.util.Stack;
  import java.util.StringTokenizer;
  
  public class teama {
  
      static int mod = 2_000_000_007;
  
      public static void main(String[] args) throws IOException {
          BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
          PrintWriter pw = new PrintWriter(System.out);
  
          int T = Integer.parseInt(br.readLine());
          for (int t = 0; t < T; t++) {
              int N = Integer.parseInt(br.readLine());
              Stack<Integer> stack = new Stack();
              for (int i = 0; i < N; i++) {
                  int a = Integer.parseInt(br.readLine());
                  if (a != 1) {
                      while (stack.peek() + 1 != a) {
                          stack.pop();
                      }
                      stack.pop();
                  }
                  stack.push(a);
  
                  boolean dummy = false;
                  for (int j : stack) {
                      if (dummy) {
                          pw.print(".");
                      }
                      pw.print(j);
                      dummy = true;
                  }
                  pw.println();
              }
          }
  
          pw.close();
          br.close();
      }
  }
  