#include <iostream>

typedef struct _Coord
{
    double x, y;
} Coord;

typedef struct _AntBase
{
    Coord * base;

    int nBaseNum;
    double dMinDist;

    void init(int n)
    {
        nBaseNum = n;
        base = new Coord[nBaseNum];
    }
} AntBase;


int g_preVisit[100];

double calcDistance(Coord coord1, Coord coord2);
double sySqrt(double x);
double detectMinDist(double dPredist, int nIndex, double * distMap, int nSize, int& nOutputIdx);

int main()
{
    int nTestNum;

    scanf("%d", &nTestNum);

    AntBase* AntracBase = new _AntBase[nTestNum];

    for (int i = 0; i < nTestNum; ++i)
    {
        int nBaseNum;
        scanf("%d", &nBaseNum);

        AntracBase[i].init(nBaseNum);

        double ** distMat = new double *[nBaseNum];
        for (int j = 0; j < nBaseNum; ++j)
        {
            distMat[j] = new double[nBaseNum];
            scanf("%lf %lf", &AntracBase[i].base[j].x, &AntracBase[i].base[j].y);
        }

        //////////////////////////////////////////////////////////////////////////

        for (int j = 0; j < nBaseNum; ++j)
        {
            for (int k = 0; k < nBaseNum; ++k)
            {
                double dist = calcDistance(AntracBase[i].base[j], AntracBase[i].base[k]);
                distMat[j][k] = dist;// = distMat[k][j] = dist;
            }
        }

        /*
        for (int j = 0; j < nBaseNum; ++j)
        {
            for (int k = 0; k < nBaseNum; ++k)
            {
                printf("%.2lf ", distMat[j][k]);
            }
            printf("\n");
        }
        */

        //////////////////////////////////////////////////////////////////////////

        double dPreDist = 0.;
        int nOutputIdx = 0;

        for (int j = 0; j < nBaseNum; ++j )
        {
            g_preVisit[j] = -1;
        }
        for (int j = 0; j < (nBaseNum - 1); ++j )
        {
            double dDiffer = detectMinDist(dPreDist, nOutputIdx, distMat[nOutputIdx], nBaseNum, nOutputIdx);
            dPreDist += dDiffer;

            g_preVisit[j] = nOutputIdx;
        }

        AntracBase[i].dMinDist = dPreDist;
    }

    //////////////////////////////////////////////////////////////////////////

    for (int i = 0; i < nTestNum; ++i)
    {
        printf("%.2lf \n", AntracBase[i].dMinDist);
    }

    return 0;
}
double calcDistance(Coord coord1, Coord coord2)
{
    double x_2 = (coord1.x - coord2.x)*(coord1.x - coord2.x);
    double y_2 = (coord1.y - coord2.y)*(coord1.y - coord2.y);

    double dDistance = sySqrt((x_2 + y_2));

    return dDistance;
}

double sySqrt(double dInput)
{
    double doutput = 1;
    for (int i = 0; i < 20; ++i)
        doutput = (doutput + (dInput / doutput)) / 2.;

    return doutput;
}

double detectMinDist(double dPredist, int nIndex, double * distMap, int nSize, int& nOutputIdx)
{
    double dMindist = 100000;
    for (int i = 0; i < nSize; ++i)
    {
        bool bPreVisit = false;
        for (int j = 0; j < nSize; ++j)
        {
            if (g_preVisit[j] == i)
            {
                bPreVisit = true;
            }
        }

        if ( (i == nIndex) || (bPreVisit) )
        {
            continue;
        }

        if ( distMap[i] < dMindist )
        {
            dMindist = distMap[i];
            nOutputIdx = i;
        }
    }

    double dDiffer = dPredist - dMindist;
    if (dDiffer < 0) dDiffer *= -1;

    if (dPredist >= dMindist)   dDiffer = 0.;

    return dDiffer;
}