import java.util.*;
public class Main {
public static void main(String args[]) {
Scanner scn = new Scanner(System.in);
int tc = scn.nextInt();
while (tc > 0) {
int n = scn.nextInt();
int[] arr = new int[n];
for (int i = 0; i < arr.length; i++)
arr[i] = scn.nextInt();
bubbleSort(arr);
for (int val : arr)
System.out.print(val);
System.out.println();
tc--;
}
}
public static void bubbleSort(int[] arr) {
int n = arr.length;
for (int count = 0; count <= n - 2; count++) {
for (int j = 0; j <= n - count - 2; j++) {
if (compare(arr[j], arr[j + 1])) {
// swap
int temp = arr[j];
arr[j] = arr[j + 1];
arr[j + 1] = temp;
}
}
}
}
public static boolean compare(int n1, int n2) {
String n1n2s = n1 + "" + n2;
String n2n1s = n2 + "" + n1;
long n1n2i = Integer.parseInt(n1n2s);
long n2n1i = Integer.parseInt(n2n1s);
if (n2n1i > n1n2i) {
return true;
} else {
return false;
}
}
}