#include<iostream>
#include<algorithm>
#include<map>
#include<cstdio>
#define ll long long
#define lson (rt<< 1)
#define rson (rt<< 1 | 1)
#define gmid ((l+r)>> 1 )
using namespace std;

const int maxn=200050;
ll a[maxn],n;
ll ans,k;
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
      {
            ans=0;k=0;
            scanf("%lld",&n);
            for(int i=1;i<=n;++i)
              scanf("%lld",&a[i]);
            sort(a+1,a+n+1);
          for(int i=2;i<=n;++i)
            k=k+a[i]-a[1];
          ans+=k;  
          for(int i=2;i<=n;++i)
            {
                k=k-(n-i+1)*(a[i]-a[i-1]);
                ans+=k;
            }          
          printf("%lld\n",ans);  
      } 
}