/***Pendulum question**/

package test;

import java.util.*;

import java.math.*;

import java.io.*;

public class ArrayQues {

public static void main(String[] args) throws IOException{

BufferedReader br = new BufferedReader (new InputStreamReader(System.in));

int T = Integer.parseInt(br.readLine());

while(T-- > 0) {

int n = Integer.parseInt(br.readLine());

ArrayList<Integer>res = new ArrayList<Integer>();

int arr[] = new int[n];

String elems[] = br.readLine().split(" ");

for(int j = 0;j<elems.length;j++)

res.add(Integer.parseInt(elems[j]));

Collections.sort(res);

int mid = res.size()%2 == 0?(res.size()-1)/2:res.size()/2;

arr[mid]= res.get(0);

int a = mid;

int k = 0;

int j = 1;

for(int i = 1;i<=mid;i++) {

if(mid+i<arr.length) {

arr[mid+i]=res.get(j);

j++;

}

if(mid-1 >= 0) {

arr[mid-i]=res.get(j);

j++;

}

}

if(res.size()%2 == 0)

arr[res.size()-1]=res.get(res.size()-1);

for(int d = 0;d<arr.length;d++)

System.out.print(arr[d]+" ");

}

}

}