import sys
from random import sample

def read_ints():
    return [int(x) for x in input().split()]

def create_network(C, L):
    ring_size = C - 1
    spur_size = L - ring_size

    # Create ring links
    nodes = list(range(1, C+1))
    ring_links = [(nodes[i], nodes[i+1]) for i in range(ring_size-1)] + [(nodes[0], nodes[-1])]
    # Add spur link
    spur_link = tuple(sample(nodes, 2))
    while spur_link in ring_links:
        spur_link = tuple(sample(nodes, 2))

    # Output links
    links = ring_links + [spur_link]
    for link in links:
        print(link[0], link[1])

    return links

def find_ring(links, perm_links):
    perm_links.sort()
    ring = [perm_links[0][0], perm_links[0][1]]
    spur = None
    for link in perm_links[1:]:
        if len(ring) == len(links)-1:
            spur = link
            break
        if link[0] == ring[-1]:
            ring.append(link[1])
        elif link[1] == ring[-1]:
            ring.append(link[0])
    if spur is None:
        spur = perm_links[0]
    ring.append(ring[0])

    return ring

T = int(input())
for t in range(T):
    C, L = read_ints()
    links = create_network(C, L)
    perm_links = [read_ints() for i in range(L)]
    ring = find_ring(links, perm_links)
    print(" ".join(str(node) for node in ring))
    sys.stdout.flush()