#include <bits/stdc++.h>

using namespace std;

int t, n;
int xa[205], xb[205], ya[205], yb[205], xx[905], yy[905];
int za[905][905], zb[905][905];
double d[905][905];
priority_queue<pair<double, pair<int, int>>, vector<pair<double, pair<int, int>>>, greater<pair<double, pair<int, int>>>> q;
int sa, sb, ta, tb;

int main() {
    scanf("%d", &t);
    while (t--) {
        map<int, int> mx, my;
        scanf("%d", &n);
        for (int i = 0; i <= n; i++) {
            scanf("%d%d%d%d", xa + i, ya + i, xb + i, yb + i);
            mx[xa[i]] = 0;
            mx[xb[i]] = 0;
            mx[xb[i] + 1] = 0;
            my[ya[i]] = 0;
            my[yb[i]] = 0;
            my[yb[i] + 1] = 0;
        }
        int ca = 0, cb = 0;
        for (auto& i : mx)
            xx[i.second = ca++] = i.first;
        for (auto& i : my)
            yy[i.second = cb++] = i.first;
        for (int i = 0; i < ca; i++)
            for (int j = 0; j < cb; j++) {
                za[i][j] = zb[i][j] = 0;
                d[i][j] = 0;
            }
        za[0][0] = zb[0][0] = 1;
        for (int i = 0; ; i++) {
            if (i == n) {
                sa = mx[xa[i]];
                sb = mx[xb[i]];
                ta = my[ya[i]];
                tb = my[yb[i]];
                break;
            }
            za[mx[xa[i]]][my[ya[i]]]++;
            za[mx[xa[i]]][my[yb[i]]]--;
            za[mx[xb[i] + 1]][my[ya[i]]]--;
            za[mx[xb[i] + 1]][my[yb[i]]]++;
            zb[mx[xa[i]]][my[ya[i]]]++;
            zb[mx[xa[i]]][my[yb[i] + 1]]--;
            zb[mx[xb[i]]][my[ya[i]]]--;
            zb[mx[xb[i]]][my[yb[i] + 1]]++;
        }
        for (int i = 0; i < ca; i++)
            for (int j = 0; j < cb; j++) {
                d[i][j] = 0;
                if (i) {
                    za[i][j] += za[i - 1][j];
                    zb[i][j] += zb[i - 1][j];
                }
                if (j) {
                    za[i][j] += za[i][j - 1];
                    zb[i][j] += zb[i][j - 1];
                }
                if (i && j) {
                    za[i][j] -= za[i - 1][j - 1];
                    zb[i][j] -= zb[i - 1][j - 1];
                }
            }
        // for (int i = 0; i < ca; i++) for (int j = 0; j < cb; j++) printf("%d%c", za[i][j], " \n"[j == cb - 1]);
        // for (int i = 0; i < ca; i++) for (int j = 0; j < cb; j++) printf("%d%c", zb[i][j], " \n"[j == cb - 1]);
        // for (int i = 0; i < ca; i++) printf("%d%c", xx[i], " \n"[i == ca - 1]);
        // for (int i = 0; i < cb; i++) printf("%d%c", yy[i], " \n"[i == cb - 1]);
        d[sa][ta] = 1;
        q.emplace(1, make_pair(sa, ta));
        // int cccc = 0;
        while (!q.empty()) {
            double di = q.top().first;
            int tx = q.top().second.first;
            int ty = q.top().second.second;
            q.pop();
            if (d[tx][ty] != di)
                continue;
            // printf("d[%d][%d]=%.5lf\n", tx, ty, d[tx][ty]);
            // if (cccc ++ > 10 ) return 0;
            if (tx) {
                double dd = di + (double)(xx[tx] - xx[tx - 1]) / zb[tx - 1][ty];
                if (d[tx - 1][ty] == 0 || dd + 1e-9 < d[tx - 1][ty])
                    q.emplace(d[tx - 1][ty] = dd, make_pair(tx - 1, ty));
            }
            if (ty) {
                double dd = di + (double)(yy[ty] - yy[ty - 1]) / za[tx][ty - 1];
                if (d[tx][ty - 1] == 0 || dd + 1e-9 < d[tx][ty - 1])
                    q.emplace(d[tx][ty - 1] = dd, make_pair(tx, ty - 1));
            }
            if (tx != ca - 1) {
                double dd = di + (double)(xx[tx + 1] - xx[tx]) / zb[tx][ty];
                if (d[tx + 1][ty] == 0 || dd + 1e-9 < d[tx + 1][ty])
                    q.emplace(d[tx + 1][ty] = dd, make_pair(tx + 1, ty));
            }
            if (ty != cb - 1) {
                double dd = di + (double)(yy[ty + 1] - yy[ty]) / za[tx][ty];
                if (d[tx][ty + 1] == 0 || dd + 1e-9 < d[tx][ty + 1])
                    q.emplace(d[tx][ty + 1] = dd, make_pair(tx, ty + 1));
            }
            // printf("%d\n", (int)q.size());
        }
        // for (int i = 0; i < ca; i++) for (int j = 0; j < cb; j++) printf("%.1lf%c", d[i][j], " \n"[j == cb - 1]);
        printf("%.5lf\n", d[sb][tb] - 1);
    }
}