source_code: import static java.lang.Integer.parseInt;
  import static java.lang.Long.parseLong;
  import static java.lang.System.arraycopy;
  import static java.lang.System.exit;
  import static java.util.Arrays.copyOf;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.NoSuchElementException;
  import java.util.StringTokenizer;
  
  public class C {
  
  	static class IntList {
  
  		int data[] = new int[3];
  		int size = 0;
  
  		boolean isEmpty() {
  			return size == 0;
  		}
  
  		int size() {
  			return size;
  		}
  
  		int get(int index) {
  			if (index < 0 || index >= size) {
  				throw new IndexOutOfBoundsException();
  			}
  			return data[index];
  		}
  
  		void clear() {
  			size = 0;
  		}
  
  		void set(int index, int value) {
  			if (index < 0 || index >= size) {
  				throw new IndexOutOfBoundsException();
  			}
  			data[index] = value;
  		}
  
  		void expand() {
  			if (size >= data.length) {
  				data = copyOf(data, (data.length << 1) + 1);
  			}
  		}
  
  		void insert(int index, int value) {
  			if (index < 0 || index > size) {
  				throw new IndexOutOfBoundsException();
  			}
  			expand();
  			arraycopy(data, index, data, index + 1, size++ - index);
  			data[index] = value;
  		}
  
  		int delete(int index) {
  			if (index < 0 || index >= size) {
  				throw new IndexOutOfBoundsException();
  			}
  			int value = data[index];
  			arraycopy(data, index + 1, data, index, --size - index);
  			return value;
  		}
  
  		void push(int value) {
  			expand();
  			data[size++] = value;
  		}
  
  		int pop() {
  			if (size == 0) {
  				throw new NoSuchElementException();
  			}
  			return data[--size];
  		}
  
  		void unshift(int value) {
  			expand();
  			arraycopy(data, 0, data, 1, size++);
  			data[0] = value;
  		}
  
  		int shift() {
  			if (size == 0) {
  				throw new NoSuchElementException();
  			}
  			int value = data[0];
  			arraycopy(data, 1, data, 0, --size);
  			return value;
  		}
  	}
  
  	static void solve() throws Exception {
  		int tests = scanInt();
  		IntList stack = new IntList();
  		for (int test = 0; test < tests; test++) {
  			stack.clear();
  			int n = scanInt();
  			for (int i = 0; i < n; i++) {
  				int v = scanInt();
  				if (v == 1) {
  					stack.push(v);
  				} else {
  					while (stack.pop() != v - 1) { }
  					stack.push(v);
  				}
  				for (int j = 0; j < stack.size; j++) {
  					if (j != 0) {
  						out.print('.');
  					}
  					out.print(stack.data[j]);
  				}
  				out.println();
  			}
  		}
  	}
  
  	static int scanInt() throws IOException {
  		return parseInt(scanString());
  	}
  
  	static long scanLong() throws IOException {
  		return parseLong(scanString());
  	}
  
  	static String scanString() throws IOException {
  		while (tok == null || !tok.hasMoreTokens()) {
  			tok = new StringTokenizer(in.readLine());
  		}
  		return tok.nextToken();
  	}
  
  	static BufferedReader in;
  	static PrintWriter out;
  	static StringTokenizer tok;
  
  	public static void main(String[] args) {
  		try {
  			in = new BufferedReader(new InputStreamReader(System.in));
  			out = new PrintWriter(System.out);
  			solve();
  			in.close();
  			out.close();
  		} catch (Throwable e) {
  			e.printStackTrace();
  			exit(1);
  		}
  	}
  }