source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.io.BufferedReader;
  import java.io.InputStreamReader;
  import java.util.*;
  import java.io.*;
  
  public class Main {
      public static void main(String[] args){
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          solve(in, out);
          out.close();
      }
  
      static String reverse(String s) {
          return (new StringBuilder(s)).reverse().toString();
      }
  
      static void sieveOfEratosthenes(int n, int factors[], ArrayList<Integer> ar) 
      { 
          factors[1]=1;
          int p;
          for(p = 2; p*p <=n; p++) 
          { 
              if(factors[p] == 0) 
              { 
                  ar.add(p);
                  factors[p]=p;
                  for(int i = p*p; i <= n; i += p) 
                      factors[i] = p; 
              } 
          } 
          for(;p<=n;p++){
              if(factors[p] == 0) 
              { 
                  ar.add(p);
              } 
          }
      }
  
      static void sort(int ar[]) {
          int n = ar.length;
          ArrayList<Integer> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static void sort1(long ar[]) {
          int n = ar.length;
          ArrayList<Long> a = new ArrayList<>();
          for (int i = 0; i < n; i++)
              a.add(ar[i]);
          Collections.sort(a);
          for (int i = 0; i < n; i++)
              ar[i] = a.get(i);
      }
  
      static long ncr(long n, long r, long mod) {
          if (r == 0)
              return 1;
          long val = ncr(n - 1, r - 1, mod);
          val = (n * val) % mod;
          val = (val * modInverse(r, mod)) % mod;
          return val;
      }
  
      static int findMax(int a[], int n, int vis[], int i, int d){
          if(i>=n)
              return 0;
          if(vis[i]==1)
              return findMax(a, n, vis, i+1, d);
          int max = 0;
          for(int j=i+1;j<n;j++){
              if(Math.abs(a[i]-a[j])>d||vis[j]==1)
                  continue;
              vis[j] = 1;
              max = Math.max(max, 1 + findMax(a, n, vis, i+1, d));
              vis[j] = 0;
          }
          return max;
      }
  
      public static void solve(InputReader sc, PrintWriter pw){
          int i, j = 0;
          // int t = 1; 
          int t = sc.nextInt();
          u: while (t-- > 0) {
              int n = sc.nextInt();
              int a[] = new int[n];
              ArrayList<Integer> ar = new ArrayList<>();
              ar.add(0);
              for(i=0;i<1000;i++){
                  ar.add(0);
              }
              int m = 1;
              for(i=0;i<n;i++){
                  a[i] = sc.nextInt();
                  if(a[i]==1){
                      ar.set(m,1);
                      m++;
                  }
                  else{
                      while(m>0&&ar.get(m-1)!=a[i]-1){
                          m--;
                      }
                      ar.set(m-1,a[i]);
                  }
                  pw.print(ar.get(1));
                  for(j=2;j<m;j++){
                      pw.print("."+ar.get(j));
                  }
                  pw.println();
              }
          }
      }
  
      static long findOne(int n, int sz[], ArrayList<Integer> ar){
          long paths = n-1;
          long till = 0;
          for(int v:ar){
              paths += till*sz[v];
              till += sz[v];
          }
          return paths;
      }
  
      static void assignAnc(ArrayList<Integer> ar[],int sz[], int pa[] ,int curr, int par){
          sz[curr] = 1;
          pa[curr] = par;
          for(int v:ar[curr]){
              if(par==v)
                  continue;
              assignAnc(ar, sz, pa, v, curr);
              sz[curr] += sz[v];
          }
      }
  
      static int findLCA(int a, int b, int par[][], int depth[]){
          if(depth[a]>depth[b]){
              a = a^b;
              b = a^b;
              a = a^b;
          }
          int diff = depth[b] - depth[a];
          for(int i=19;i>=0;i--){
              if((diff&(1<<i))>0){
                  b = par[b][i];
              }
          }
          if(a==b)
              return a;
          for(int i=19;i>=0;i--){
              if(par[b][i]!=par[a][i]){
                  b = par[b][i];
                  a = par[a][i];
              }
          }
          return par[a][0];
      }
  
      static void formArrayForBinaryLifting(int n, int par[][]){
          for(int j=1;j<20;j++){
              for(int i=0;i<n;i++){
                  if(par[i][j-1]==-1)
                      continue;
                  par[i][j] = par[par[i][j-1]][j-1];
              }
          }
      }
  
      static long lcm(int a, int b){
          return a*b/gcd(a,b);
      }
  
      static class Pair1 {
          long a;
          long b;
          
          Pair1(long a, long b) {
              this.a = a;
              this.b = b;
          }
      }
  
      static class Pair implements Comparable<Pair> {
          int a;
          int b;
          int c;
          
          Pair(int a, int b, int c) {
              this.a = a;
              this.b = b;
              this.c = c;
          }
   
          public int compareTo(Pair p) {
              // if(a!=p.a)
              //     return a-p.a;
              // return b-p.b;
              return p.c - c;
          }
      }
  
      // static boolean isPrime(long n) {
      //     if (n <= 1)
      //         return false;
      //     if (n <= 999)
      //         return true;
      //     if (n % 2 == 0 || n % 999 == 0)
      //         return false;
      //     for (int i = 5; i * i <= n; i = i + 6)
      //         if (n % i == 0 || n % (i + 2) == 0)
      //             return false;
      //     return true;
      // }
  
      static long gcd(long a, long b) {
          if (b == 0)
              return a;
          return gcd(b, a % b);
      }
  
      static long fast_pow(long base, long n, long M) {
          if (n == 0)
              return 1;
          if (n == 1)
              return base % M;
          long halfn = fast_pow(base, n / 2, M);
          if (n % 2 == 0)
              return (halfn * halfn) % M;
          else
              return (((halfn * halfn) % M) * base) % M;
      }
  
      static long modInverse(long n, long M) {
          return fast_pow(n, M - 2, M);
      }
  
      static class InputReader {
          public BufferedReader reader;
          public StringTokenizer tokenizer;
  
          public InputReader(InputStream stream) {
              reader = new BufferedReader(new InputStreamReader(stream), 9992768);
              tokenizer = null;
          }
  
          public String next() {
              while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                  try {
                      tokenizer = new StringTokenizer(reader.readLine());
                  } catch (IOException e) {
                      throw new RuntimeException(e);
                  }
              }
              return tokenizer.nextToken();
          }
  
          public int nextInt() {
              return Integer.parseInt(next());
          }
  
          public long nextLong() {
              return Long.parseLong(next());
          }
      }
  }