def test_distance_is_quantity():
"""
test that distance behaves like a proper quantity
"""
Distance(2 * u.kpc)
d = Distance([2, 3.1], u.kpc)
assert d.shape == (2, )
a = d.view(np.ndarray)
q = d.view(u.Quantity)
a[0] = 1.2
q.value[1] = 5.4
assert d[0].value == 1.2
assert d[1].value == 5.4
q = u.Quantity(d, copy=True)
q.value[1] = 0
assert q.value[1] == 0
assert d.value[1] != 0
# regression test against #2261
d = Distance([2 * u.kpc, 250. * u.pc])
assert d.unit is u.kpc
assert np.all(d.value == np.array([2., 0.25]))
