/*
 -> Written by <-
   -----------
  |J_O_B_E_E_L|
  |___________|
  |    ___    |
  |   (^_^)   |
  |  /( | )\  |
  |____|_|____|
*/

import java.lang.reflect.Array;
import java.util.*;
import java.io.*;
import java.lang.*;
import java.math.*;
import java.nio.file.Path;
import java.util.Map.*;

  
public class Test {
	public static void main(String[] args) throws Exception {
		int t=sc.nextInt();
		 out: while(t-->0) {
			int x=sc.nextInt(); 
			int maxneg=-(Integer.MAX_VALUE);
			int maxpos=0;
			for(int i=0;i<x;i++) {
				int y=sc.nextInt();
				if(y>=0) maxpos=Math.max(maxpos, y);
				else maxneg=Math.max(maxneg, y);
			}
			if(maxneg==-(Integer.MAX_VALUE)) pw.println(maxpos);
			else if(maxpos==0)pw.println(maxneg);
			else pw.println(maxneg+maxpos);
		}
		pw.flush();
		pw.close();
	}
	

    static class Scanner {
    	 
        private InputStream in;
        private byte[] buffer = new byte[1024];
        private int curbuf;
        private int lenbuf;
 
        public Scanner(InputStream in) {
            this.in = in;
            this.curbuf = this.lenbuf = 0;
        }
 
        public boolean hasNextByte() {
            if (curbuf >= lenbuf) {
                curbuf = 0;
                try {
                    lenbuf = in.read(buffer);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (lenbuf <= 0)
                    return false;
            }
            return true;
        }
 
        private int readByte() {
            if (hasNextByte())
                return buffer[curbuf++];
            else
                return -1;
        }
 
        private boolean isSpaceChar(int c) {
            return !(c >= 33 && c <= 126);
        }
 
        private void skip() {
            while (hasNextByte() && isSpaceChar(buffer[curbuf]))
                curbuf++;
        }
 
        public boolean hasNext() {
            skip();
            return hasNextByte();
        }
 
        public String next() {
            if (!hasNext())
                throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while (!isSpaceChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
 
        public int nextInt() {
            if (!hasNext())
                throw new NoSuchElementException();
            int c = readByte();
            while (isSpaceChar(c))
                c = readByte();
            boolean minus = false;
            if (c == '-') {
                minus = true;
                c = readByte();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res = res * 10 + c - '0';
                c = readByte();
            } while (!isSpaceChar(c));
            return (minus) ? -res : res;
        }
 
        public long nextLong() {
            if (!hasNext())
                throw new NoSuchElementException();
            int c = readByte();
            while (isSpaceChar(c))
                c = readByte();
            boolean minus = false;
            if (c == '-') {
                minus = true;
                c = readByte();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res = res * 10 + c - '0';
                c = readByte();
            } while (!isSpaceChar(c));
            return (minus) ? -res : res;
        }
 
        public double nextDouble() {
            return Double.parseDouble(next());
        }
 
        public int[] nextIntArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }
 
        public long[] nextLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }
        
        public Long [] nextSortedLongArray(int n) {
        	Long [] a=new Long[n];
        	for(int i=0;i<n;i++) a[i]=sc.nextLong();
        	Arrays.sort(a);
        	return a;
        }
        public Integer [] nextSortedIntegerArray(int n) {
        	Integer [] a=new Integer[n];
        	for(int i=0;i<n;i++) a[i]=sc.nextInt();
        	Arrays.sort(a);
        	return a;
        }
 
    }
 


   
	static PrintWriter pw=new PrintWriter(System.out);
	static Scanner sc=new Scanner(System.in);
 
}
