#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int a[100005];ll ans,now;
int read(){
    int res=0,op=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')op=-1;ch=getchar();}
    while(isdigit(ch))res=res*10+ch-'0',ch=getchar();
    return res*op;
}
void write(ll x){
    if(x<0)putchar('-'),x=-x;
    if(x>9)write(x/10);
    putchar(x%10+48);
}
void solve(){
    int n=read();
    for(int i=1;i<=n;i++)a[i]=read();
    sort(a+1,a+n+1);
    now=0;ans=0;
    for(int i=1;i<=n;i++){
        now+=a[i],ans+=(ll)a[i]*i-now;
    }
    write(ans);puts("");
}
int main()
{
    int es=read();
    while(es--)
    solve();
    return 0;
}