def test_get_layer_slice_fail(self):
la = LayeredArray()
with raises(IndexError):
la.get_layer_slice(0)
def test_get_layer_slice(self):
la = LayeredArray()
la.close_layer()
layer_slice = la.get_layer_slice(0)
assert layer_slice.start == 0
assert layer_slice.stop == 0