source_code: import java.lang.*;
  import java.util.*;
  import java.io.*;
  
  public class Main {    
      static void deal(int n,int[] arr) {
          int[] a = new int[n];
          a[0] = 1;
          int l = 1;
          out.println(toString(a,l));
          for(int i=1;i<n;i++) {
              if(arr[i] == 1) {
                  a[l] = 1;
                  l++;
              } else {
                  int index = l-1;
                  while(index>=0 && a[index] != arr[i]-1) {
                      index--;
                  }
                  a[index]++;
                  l = index+1;
              }
              out.println(toString(a,l));
          }
      }
      
      static String toString(int[] arr,int l) {
          StringBuilder sb = new StringBuilder();
          for(int i=0;i<l-1;i++) {
              sb.append(arr[i]);
              sb.append('.');
          }
          sb.append(arr[l-1]);
          return sb.toString();
      }
      
  	public static void main(String[] args) {
          MyScanner sc = new MyScanner();
          out = new PrintWriter(new BufferedOutputStream(System.out));
          int t = sc.nextInt();
          for(int i=0;i<t;i++) {
              int n = sc.nextInt();
              int[] arr = new int[n];
              for(int j=0;j<n;j++) arr[j] = sc.nextInt();
              deal(n,arr);
          }
          out.close();
      }
      
      //-----------PrintWriter for faster output---------------------------------
      public static PrintWriter out;
      
      //-----------MyScanner class for faster input----------
      public static class MyScanner {
          BufferedReader br;
          StringTokenizer st;
          
          public MyScanner() {
                  br = new BufferedReader(new InputStreamReader(System.in));
          }
          
          String next() {
                  while (st == null || !st.hasMoreElements()) {
                          try {
                                  st = new StringTokenizer(br.readLine());
                          } catch (IOException e) {
                                  e.printStackTrace();
                          }
                  }
                  return st.nextToken();
          }
          
          int nextInt() {
                  return Integer.parseInt(next());
          }
          
          long nextLong() {
                  return Long.parseLong(next());
          }
          
          double nextDouble() {
                  return Double.parseDouble(next());
          }
          
          String nextLine(){
                  String str = "";
      try {
              str = br.readLine();
      } catch (IOException e) {
              e.printStackTrace();
      }
      return str;
          }
          
      }
  }