from skyfield.api import load
from skyfield.magnitudelib import planetary_magnitude

def test_magnitudes():
    ts = load.timescale()
    #t = ts.utc(1995, 5, 22)  # Rings edge-on from Earth.
    t = ts.utc(2021, 10, 4)
    eph = load('de421.bsp')
    earth = eph['earth']
    names = [
        'mercury', 'venus', 'mars', 'jupiter barycenter',
        'saturn barycenter', 'uranus barycenter', 'neptune barycenter',
    ]
    e = earth.at(t)
    positions = [e.observe(eph[name]) for name in names]
    magnitudes = [planetary_magnitude(position) for position in positions]
    assert ['%.3f' % m for m in magnitudes] == [
        '2.393', '-4.278', '1.592', '-2.693', '0.508', '5.701', '7.690',
    ]

    t = ts.tt_jd([t.tt, t.tt])
    e = earth.at(t)
    positions = [e.observe(eph[name]) for name in names]
    magnitudes = [planetary_magnitude(position) for position in positions]
    assert [['%.3f' % m for m in mm] for mm in magnitudes] == [
        ['2.393', '2.393'],
        ['-4.278', '-4.278'],
        ['1.592', '1.592'],
        ['-2.693', '-2.693'],
        ['0.508', '0.508'],
        ['5.701', '5.701'],
        ['7.690', '7.690'],
    ]