#include<bits/stdc++.h>
#define fo(i,a,b) for(int i=a;i<=b;++i)
#define fod(i,a,b) for(int i=a;i>=b;--i)
#define max(q,w) ((q)>(w)?(q):(w))
#define min(q,w) ((q)<(w)?(q):(w))
using namespace std;
typedef long long LL;
const int N=100500,INF=1e9;
int read(int &n)
{
    int q=1;n=0;char ch=' ';
    for(;ch!='-'&&(ch<'0'||ch>'9');ch=getchar());
    if(ch=='-')q=-1,ch=getchar();
    for(;ch<='9'&&ch>='0';ch=getchar())n=(n<<1)+(n<<3)+ch-48;
    return n;
}
int n,m;
int a[N];
LL ans;
int main()
{
    int q,w,_;
    read(_);
    while(_--)
    {
        read(n);
        LL t=0;
        fo(i,1,n)t+=(LL)read(a[i]);
        sort(a+1,a+1+n);
        ans=0;
        fo(i,1,n)
        {
            t-=a[i];
            ans+=t-(LL)a[i]*(n-i);
        }
        printf("%lld\n",ans);
    }

    return 0;
}