source_code: import java.util.LinkedList;
  import java.util.Queue;
  import java.util.Scanner;
  import java.util.Stack;
  
  public class C{
      public static void main(String args[])
      {
          Scanner sc=new Scanner(System.in);
          long mod=1000000007l;
          int cases=sc.nextInt();
  
  
          while(cases>0)
          {
              cases--;
              Stack<Integer> stack=new Stack<>();
  
              int n=sc.nextInt();
  
              for(int j=0;j<n;j++)
              {
                  int x=sc.nextInt();
                  if(x==1)
                  {
                      stack.add(1);
                  }
                  else
                  {
                      int p=stack.pop();
                      if(p==x-1)
                      {
                          stack.add(x);
                      }
                      else {
                          while (p != x-1) {
                              p = stack.pop();
                          }
  
                          stack.add(x);
  
                      }
  
                  }
                  StringBuilder f=new StringBuilder();
                  Stack<Integer> temp=new Stack<>();
  
                  while(stack.isEmpty()==false)
                  {
                      temp.add(stack.pop());
                  }
  
                  while(temp.isEmpty()==false)
                  {
                      int z=temp.pop();
                      f.append(z+".");
                      stack.add(z);
                  }
  
  
                  System.out.println(f.substring(0,f.length()-1));
  
              }
  
          }
  
      }
  }
  