#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const int MOD = 1e9+7;

int gcd(int a, int b) { return b == 0 ? a : gcd(b, a % b); }

int lcm(int a, int b) { return (a / gcd(a, b)) * b; }

int modpow(int a, int b, int mod = MOD) {

int res = 1;

while (b) {

if (b & 1) res = (res * a) % mod;

a = (a * a) % mod;

b >>= 1;

}

return res;

}

vector<int> sieve(int n) {

vector<int> isPrime(n + 1, 1);

isPrime[0] = isPrime[1] = 0;

for (int i = 2; i*i <= n; i++)

if (isPrime[i])

for (int j = i*i; j <= n; j += i)

isPrime[j] = 0;

return isPrime;

}

void solve(){

ll n, m;

cin>>n>>m;

vector<ll> v(n);

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

sort(v.begin(),v.end());

if(m<n){

ll mul=1;

ll ans=0;

for(int i=n-m;i<n;i++){

ans+=1ll*(mul*v[i]);

mul++;

}

cout<<ans<<endl;

return;

}

ll ans =0;

ll mul=1;

while(m!=(n-1)){

ans += v[0];

m--;

mul++;

}

for(int i=1;i<n;i++){

ans+=1ll*(mul*v[i]);

mul++;

}

cout<<ans<<endl;

}

int main(){

ios::sync_with_stdio(0);

cin.tie(0);

int t = 1;

cin>>t;

while (t--)

{

solve();

}

}