#include<bits/stdc++.h>

using namespace std;

#define LCM(a,b)                (a / __gcd(a,b) ) *b
#define GCD(a,b)                __gcd(a,b)
#define dist(x1,y1,x2,y2)       sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))
#define distl(x1,y1,x2,y2)      sqrtl((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))
#define fRead(x)                freopen(x,"r",stdin)
#define fWrite(x)               freopen (x,"w",stdout)
#define LL                      long long
#define ULL                     unsigned long long
#define pb                      push_back
#define tcase                   cout<<"Case "<<C++<<": ";
#define all(a)                  a.begin(),a.end()
#define Unique(a)               sort(all(a)),a.erase(unique(all(a)),a.end
#define ABS(x)                  ((x)<0?-(x):(x))
#define min3(a,b,c)             min(a,min(b,c))
#define min4(a,b,c,d)           min(a,min(b,min(c,d)))
#define max3(a,b,c)             max(a,max(b,c))
#define max4(a,b,c,d)           max(a,max(b,max(c,d)))
#define PI                      acos(-1.0)
#define ff                      first
#define ss                      second
#define SP(x,y)                 fixed<<setprecision((y))<<(x)
#define FastRead                ios_base::sync_with_stdio(0);cin.tie(NULL);
#define FOR(x, l, r)            for (int x = l; x<=r; ++x)
#define REP(x,r)                for (int x = 0; x <r; ++x)
#define NN                      cout<<"\n";
#define NNN                     cout<<"\n------------------------------\n";

//***********************************************************************//
//                      SHAHED AHMED, CSE'15, IUT                        //
//***********************************************************************//


int main()
{
    FastRead
    LL T;
    cin>>T;

    while(T--)
    {
        int n;
        cin>>n;
        vector<LL> v(n);

        for(int i=0; i<n; i++)
        {
            cin>>v[i];
        }

        sort(all(v));

        LL tot = 0;
        LL sum = 0;
        for(int i=1; i<n; i++)
        {
            tot += v[i]*i - sum;
            sum+=v[i];
        }

        cout<<tot*-1 + v[n-1]<<"\n";
    }

}
