def test_issue_3871():
    z = Symbol("z", positive=True)
    f = -1/z*exp(-z*x)
    assert limit(f, x, oo) == 0
    assert f.limit(x, oo) == 0
dataset/ETHPy150Open sympy/sympy/sympy/series/tests/test_limits.py/test_issue_3871/original