import java.util.List;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.ArrayList;
import java.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.StringTokenizer;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Praveen
 */
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);
            ANUUND solver = new ANUUND();
            int testCount = Integer.parseInt(in.next());
            for (int i = 1; i <= testCount; i++)
                  solver.solve(i, in, out);
            out.close();
      }
}

class ANUUND {
    public void solve(int testNumber, InputReader in, PrintWriter out) {
        int n = in.nextInt();
        int []a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = in.nextInt();
        }
        Arrays.sort(a);
        int left = 0, right = n - 1;
        List<Integer> list = new ArrayList<>();
        while (left < right) {
            list.add(a[left]);
            list.add(a[right]);
            left ++;
            right --;
        }
        if (left == right) {
            list.add(a[left]);
        }
        if (list.size() != n) throw new RuntimeException("Something Wrong Happened");
        for (int i = 0; i < n; i++) {
            if (i > 0) out.print (" ");
            out.print (list.get(i));
        }
        out.print("\n");
    }
}

class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
        reader = new BufferedReader(new InputStreamReader(stream), 32768);
        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());
    }

}