import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.*;

public class B {
	
	public static void main(String[] args) throws IOException {
		
		Reader scan = new Reader();
		int t = scan.nextInt();
		for(int tt = 0;tt<t;tt++) {
			
			int n = scan.nextInt();
			int arr[] = new int[n];
			for(int i = 0;i<n;i++) arr[i] = scan.nextInt();
			
			List<Integer> list = new ArrayList<>();
			int j = -1;
			StringBuilder s = new StringBuilder();
			for(int i = 0;i<n;i++) {
				if(list.isEmpty() || arr[i]==1) { //add
					list.add(arr[i]);
					j++;
				}
				else if(arr[i] == list.get(j)+1) { //replace
					list.set(j, arr[i]);
				}
				else {
					for(int k = j;k>=0;k--) {
						if(arr[i] == list.get(k)+1) {//replace
							list.set(k, arr[i]);
							break;
						}
						else {//delete
							list.remove(k);
							j--;
						}
					}
				}
				s.delete(0, s.length());
				for(Integer p:list) {
					s.append(p+".");
				}
				s.deleteCharAt(s.length()-1);
				System.out.println(s.toString());
			}
		}

		scan.close();
		
	}
	
	static class Reader 
	{ 
		final private int BUFFER_SIZE = 1 << 16; 
		private DataInputStream din; 
		private byte[] buffer; 
		private int bufferPointer, bytesRead; 

		public Reader() 
		{ 
			din = new DataInputStream(System.in); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public Reader(String file_name) throws IOException 
		{ 
			din = new DataInputStream(new FileInputStream(file_name)); 
			buffer = new byte[BUFFER_SIZE]; 
			bufferPointer = bytesRead = 0; 
		} 

		public String readLine() throws IOException 
		{ 
			byte[] buf = new byte[64]; // line length 
			int cnt = 0, c; 
			while ((c = read()) != -1) 
			{ 
				if (c == '\n') 
					break; 
				buf[cnt++] = (byte) c; 
			} 
			return new String(buf, 0, cnt); 
		} 

		public int nextInt() throws IOException 
		{ 
			int ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do
			{ 
				ret = ret * 10 + c - '0'; 
			}  while ((c = read()) >= '0' && c <= '9'); 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		public long nextLong() throws IOException 
		{ 
			long ret = 0; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 
			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 
			if (neg) 
				return -ret; 
			return ret; 
		} 

		public double nextDouble() throws IOException 
		{ 
			double ret = 0, div = 1; 
			byte c = read(); 
			while (c <= ' ') 
				c = read(); 
			boolean neg = (c == '-'); 
			if (neg) 
				c = read(); 

			do { 
				ret = ret * 10 + c - '0'; 
			} 
			while ((c = read()) >= '0' && c <= '9'); 

			if (c == '.') 
			{ 
				while ((c = read()) >= '0' && c <= '9') 
				{ 
					ret += (c - '0') / (div *= 10); 
				} 
			} 

			if (neg) 
				return -ret; 
			return ret; 
		} 

		private void fillBuffer() throws IOException 
		{ 
			bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE); 
			if (bytesRead == -1) 
				buffer[0] = -1; 
		} 

		private byte read() throws IOException 
		{ 
			if (bufferPointer == bytesRead) 
				fillBuffer(); 
			return buffer[bufferPointer++]; 
		} 

		public void close() throws IOException 
		{ 
			if (din == null) 
				return; 
			din.close(); 
		} 
	}

}
