source_code: import java.io.*;
  import java.math.BigInteger;
  import java.util.*;
  import java.util.concurrent.TimeUnit;
  
  public class c1523 implements Runnable{
  	
      public static void main(String[] args) {
      	try{
              new Thread(null, new c1523(), "process", 1<<26).start();
          }
          catch(Exception e){
              System.out.println(e);
          }
      }
  	public void run() {
  		FastReader scan = new FastReader();
          PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
  		//PrintWriter out = new PrintWriter("file.out");
  		Task solver = new Task();
  		int t = scan.nextInt();
  		//int t = 1;
  		for(int i = 1; i <= t; i++) solver.solve(i, scan, out);
  		out.close();
  	}
  
  	static class Task {
  		static final int oo = Integer.MAX_VALUE;
  		static final long OO = Long.MAX_VALUE;
  
  		public void solve(int testNumber, FastReader sc, PrintWriter out) {
  			int N = sc.nextInt();
  			int[] arr = sc.readArray(N);
  			
  			Stack<Integer> cur = new Stack<>();
  			StringBuilder sb = new StringBuilder("");
  			for(int i = 0; i < N; i++) {
  				if(arr[i] == 1) {
  					cur.add(1);
  				} else {
  					while(cur.peek() != arr[i] - 1)
  						cur.pop();
  					cur.pop();
  					cur.add(arr[i]);
  				}
  				
  				for(int each: cur) {
  					sb.append(each + ".");
  				}
  				sb.deleteCharAt(sb.length()-1);
  				sb.append("\n");
  			}
  			
  			out.println(sb);
  		}
  		
  	}
  	static long modInverse(long N, long MOD) {
  		return binpow(N, MOD - 2, MOD);
  	}
  	static long modDivide(long a, long b, long MOD) {
  		a %= MOD;
  		return (binpow(b, MOD-2, MOD) * a) % MOD;
  	}
  	static long binpow(long a, long b, long m) {
  		a %= m;
  		long res = 1;
  		while (b > 0) {
  			if ((b & 1) == 1)
  				res = res * a % m;
  			a = a * a % m;
  			b >>= 1;
  		}
  		return res;
  	}
  	static int[] reverse(int a[]) 
      { 
          int[] b = new int[a.length]; 
          for (int i = 0, j = a.length; i < a.length; i++, j--) { 
              b[j - 1] = a[i]; 
          } 
          
          return b;
      }
  	static long[] reverse(long a[]) 
      { 
          long[] b = new long[a.length]; 
          for (int i = 0, j = a.length; i < a.length; i++, j--) { 
              b[j - 1] = a[i]; 
          } 
          
          return b;
      }
  	
  	static void shuffle(Object[] a) {
  		Random get = new Random();
  		for (int i = 0; i < a.length; i++) {
  			int r = get.nextInt(a.length);
  			Object temp = a[i];
  			a[i] = a[r];
  			a[r] = temp;
  		}
  	}
  	
  	static void shuffle(int[] a) {
  		Random get = new Random();
  		for (int i = 0; i < a.length; i++) {
  			int r = get.nextInt(a.length);
  			int temp = a[i];
  			a[i] = a[r];
  			a[r] = temp;
  		}
  	}
  	static void shuffle(long[] a) {
  		Random get = new Random();
  		for (int i = 0; i < a.length; i++) {
  			int r = get.nextInt(a.length);
  			long temp = a[i];
  			a[i] = a[r];
  			a[r] = temp;
  		}
  	}
  	
  	static class tup implements Comparable<tup>, Comparator<tup>{
  		int a, b;
  		tup(int a,int b){
  			this.a=a;
  			this.b=b;
  		}
  		public tup() {
  		}
  		@Override
  		public int compareTo(tup o){
  			return Integer.compare(b,o.b);
  		}
  		@Override
  		public int compare(tup o1, tup o2) {
  			return Integer.compare(o1.b, o2.b);
  		}
  		
  		@Override
  	    public int hashCode() {
  			return Objects.hash(a, b);
  	    }
   
  	    @Override
  	    public boolean equals(Object obj) {
  	    	if (this == obj)
                  return true;
  	    	if (obj == null)
                  return false;
  	    	if (getClass() != obj.getClass())
                  return false;
  	    	tup other = (tup) obj;
  	    	return a==other.a && b==other.b;
  	    }
  	    
  	    @Override
  	    public String toString() {
  	    	return a + " " + b;
  	    }
  	}
  
  	static class FastReader {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public FastReader() {
  			br = new BufferedReader(new InputStreamReader(System.in));
  		}
  
  		public FastReader(String s) throws FileNotFoundException {
  			br = new BufferedReader(new FileReader(new File(s)));
  		}
  
  		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;
  		}
  		
  		int[] readArray(int size) {
  			int[] a = new int[size];
  			for(int i = 0; i < size; i++) {
  				a[i] = nextInt();
  			}
  			return a;
  		}
  		
  		long[] readLongArray(int size) {
  			long[] a = new long[size];
  			for(int i = 0; i < size; i++) {
  				a[i] = nextLong();
  			}
  			return a;
  		}
  	}
  	
  	static void dbg(int[] arr) {
  		System.out.println(Arrays.toString(arr));
  	}
  	static void dbg(long[] arr) {
  		System.out.println(Arrays.toString(arr));
  	}
  	static void dbg(boolean[] arr) {
  		System.out.println(Arrays.toString(arr));
  	}
  
  	static void dbg(Object... args) {
          for (Object arg : args)
              System.out.print(arg + " ");
          System.out.println();
      }
  }