#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define REP(i,n) for(int i=0;i<(n);i++)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;

template<class T> void read(T &x){
    int f=0; x=0; char ch=getchar();
    for(;!isdigit(ch);ch=getchar()) f|=(ch=='-');
    for(;isdigit(ch);ch=getchar()) x=x*10+ch-'0';
    if(f) x=-x;
}

const int N=100005;
ll a[N],n;

void rmain(){
    read(n);
    rep(i,1,n){
        read(a[i]);
    }
    sort(a+1,a+n+1);
    ll ans=0;
    rep(i,1,n){
        ans+=a[i]*(i-1-(n-i));
    }
    cout<<ans<<endl;
}

int main(){
    int T; read(T);
    while(T--) rmain();
    return 0;
}