source_code: import java.util.*;
  import java.io.*;
  
  public class C1523 {
  	public static void print(Stack<Integer> st, PrintWriter pw) {
  		for (int i = 0; i < st.size(); i++) {
  			pw.print(st.get(i));
  			if (i != st.size() - 1) {
  				pw.print(".");
  			}
  		}
  		pw.println();
  	}
  
  	public static void main(String[] args) throws IOException {
  		Scanner sc = new Scanner(System.in);
  		PrintWriter pw = new PrintWriter(System.out);
  		int t = sc.nextInt();
  		while (t-- > 0) {
  			int n = sc.nextInt();
  			int[] arr = sc.nextIntArr(n);
  			Stack<Integer> st = new Stack<Integer>();
  			st.add(arr[0]);
  			print(st, pw);
  			for (int i = 1; i < n; i++) {
  				if (arr[i] == 1) {
  					st.add(arr[i]);
  				} else {
  					while (st.peek() != arr[i] - 1) {
  						st.pop();
  					}
  					st.pop();
  					st.add(arr[i]);
  				}
  				print(st, pw);
  			}
  		}
  		pw.close();
  	}
  
  	static class Scanner {
  		BufferedReader br;
  		StringTokenizer st;
  
  		public Scanner(InputStream s) {
  			br = new BufferedReader(new InputStreamReader(s));
  		}
  
  		public Scanner(FileReader f) {
  			br = new BufferedReader(f);
  		}
  
  		public String next() throws IOException {
  			while (st == null || !st.hasMoreTokens())
  				st = new StringTokenizer(br.readLine());
  			return st.nextToken();
  		}
  
  		public int nextInt() throws IOException {
  			return Integer.parseInt(next());
  		}
  
  		public long nextLong() throws IOException {
  			return Long.parseLong(next());
  		}
  
  		public double nextDouble() throws IOException {
  			return Double.parseDouble(next());
  		}
  
  		public int[] nextIntArr(int n) throws IOException {
  			int[] arr = new int[n];
  			for (int i = 0; i < n; i++) {
  				arr[i] = Integer.parseInt(next());
  			}
  			return arr;
  		}
  
  	}
  
  }
  