def test_floyd():
tt = Timetrip(4)
for w in '0 2 0\n2 2 -1\n2 1 0'.split('\n'):
tt.fill_graph(w)
dist, via = tt.floyd()
assert tt.has_cycle(via) == True
def test_minus_cycle2():
tt = Timetrip(4)
for w in '0 0 -2\n0 3 1\n2 3 1\n3 2 2\n2 1 0'.split('\n'):
tt.fill_graph(w)
dist, via = tt.floyd()
print(via)
assert tt.has_cycle(via) == True
solution = tt.solve()
assert solution == ('INFINITY', 'INFINITY')