int t;
cin >> t;
while(t--)
{
long long int n;
cin >> n;
long long int* arr= new long long int[n];
for(int i = 0; i<n; i++)
cin >> arr[i];
long long int diff = 0;
for(int i = 1; i<n; i++)
{
diff += abs(arr[i] - arr[i-1])-1;
//cout << diff << endl;
}
cout << diff << endl;
}