import numpy as np
from scipy.optimize import linprog

for _ in range(int(input())):
    n, m = map(int, input().split())
    A = [list(map(float, input().split())) + [-1.0] for _ in range(n)]
    # print(A)

    A.append([1.0] * m + [0.])
    A.append([-1.0] * m + [0.])
    A = np.array(A)

    b_ub = np.array([0.] * n + [1.0, -1.0])

    C = np.array([0.] * m + [1.])

    bounds = [(0., None)] * m + [(None, None)]

    lp = linprog(c=C, A_ub=A, b_ub=b_ub, bounds=bounds)
    # print(lp.x)
    print(lp.fun)