def test_in(neuron_instance):
    """Test 1D diffusion in a single section"""

    h, rxd, data, save_path = neuron_instance

    soma = h.Section(name="soma")
    dend = h.Section(name="dend")
    soma.nseg = 3

    cyt = rxd.Region(h.allsec(), name="cyt")
    er = rxd.Region(h.allsec(), name="er")

    c = rxd.Species(cyt, name="c")

    for node in c.nodes(soma):
        assert node in soma
        assert node not in dend
        assert node in cyt
        assert node not in er

    for node in c.nodes(dend):
        assert node in dend
        assert node not in soma
        assert node in cyt
        assert node not in er