test_solarposition.py

import calendar
import datetime
import warnings

import numpy as np
import pandas as pd

from .conftest import (
    assert_frame_equal,
    assert_series_equal,
    fail_on_pvlib_version,
)
from numpy.testing import assert_allclose
import pytest

from pvlib.location import Location
from pvlib import solarposition, spa

from .conftest import (
    requires_ephem, requires_spa_c, requires_numba, requires_pandas_2_0
)

# setup times and locations to be tested.
times = pd.date_range(start=datetime.datetime(2014, 6, 24),
                      end=datetime.datetime(2014, 6, 26), freq='15min')

tus = Location(32.2, -111, 'US/Arizona', 700)  # no DST issues possible
times_localized = times.tz_localize(tus.tz)

tol = 5


@pytest.fixture()
def expected_solpos_multi():
    return pd.DataFrame({'elevation': [39.872046, 39.505196],
                         'apparent_zenith': [50.111622, 50.478260],
                         'azimuth': [194.340241, 194.311132],
                         'apparent_elevation': [39.888378, 39.521740]},
                        index=['2003-10-17T12:30:30Z', '2003-10-18T12:30:30Z'])


@pytest.fixture()
def expected_rise_set_spa():
    # for Golden, CO, from NREL SPA website
    times = pd.DatetimeIndex([datetime.datetime(2015, 1, 2),
                              datetime.datetime(2015, 8, 2),
                              ]).tz_localize('MST')
    sunrise = pd.DatetimeIndex([datetime.datetime(2015, 1, 2, 7, 21, 55),
                                datetime.datetime(2015, 8, 2, 5, 0, 27)
                                ]).tz_localize('MST').tolist()
    sunset = pd.DatetimeIndex([datetime.datetime(2015, 1, 2, 16, 47, 43),
                               datetime.datetime(2015, 8, 2, 19, 13, 58)
                               ]).tz_localize('MST').tolist()
    transit = pd.DatetimeIndex([datetime.datetime(2015, 1, 2, 12, 4, 45),
                                datetime.datetime(2015, 8, 2, 12, 6, 58)
                                ]).tz_localize('MST').tolist()
    return pd.DataFrame({'sunrise': sunrise,
                         'sunset': sunset,
                         'transit': transit},
                        index=times)


@pytest.fixture()
def expected_rise_set_ephem():
    # for Golden, CO, from USNO websites
    times = pd.DatetimeIndex([datetime.datetime(2015, 1, 1),
                              datetime.datetime(2015, 1, 2),
                              datetime.datetime(2015, 1, 3),
                              datetime.datetime(2015, 8, 2),
                              ]).tz_localize('MST')
    sunrise = pd.DatetimeIndex([datetime.datetime(2015, 1, 1, 7, 22, 0),
                                datetime.datetime(2015, 1, 2, 7, 22, 0),
                                datetime.datetime(2015, 1, 3, 7, 22, 0),
                                datetime.datetime(2015, 8, 2, 5, 0, 0)
                                ]).tz_localize('MST').tolist()
    sunset = pd.DatetimeIndex([datetime.datetime(2015, 1, 1, 16, 47, 0),
                               datetime.datetime(2015, 1, 2, 16, 48, 0),
                               datetime.datetime(2015, 1, 3, 16, 49, 0),
                               datetime.datetime(2015, 8, 2, 19, 13, 0)
                               ]).tz_localize('MST').tolist()
    transit = pd.DatetimeIndex([datetime.datetime(2015, 1, 1, 12, 4, 0),
                                datetime.datetime(2015, 1, 2, 12, 5, 0),
                                datetime.datetime(2015, 1, 3, 12, 5, 0),
                                datetime.datetime(2015, 8, 2, 12, 7, 0)
                                ]).tz_localize('MST').tolist()
    return pd.DataFrame({'sunrise': sunrise,
                         'sunset': sunset,
                         'transit': transit},
                        index=times)


# the physical tests are run at the same time as the NREL SPA test.
# pyephem reproduces the NREL result to 2 decimal places.
# this doesn't mean that one code is better than the other.

@requires_spa_c
def test_spa_c_physical(expected_solpos, golden_mst):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 12, 30, 30),
                          periods=1, freq='D', tz=golden_mst.tz)
    ephem_data = solarposition.spa_c(times, golden_mst.latitude,
                                     golden_mst.longitude,
                                     pressure=82000,
                                     temperature=11)
    expected_solpos.index = times
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


@requires_spa_c
def test_spa_c_physical_dst(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.spa_c(times, golden.latitude,
                                     golden.longitude,
                                     pressure=82000,
                                     temperature=11)
    expected_solpos.index = times
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


def test_spa_python_numpy_physical(expected_solpos, golden_mst):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 12, 30, 30),
                          periods=1, freq='D', tz=golden_mst.tz)
    ephem_data = solarposition.spa_python(times, golden_mst.latitude,
                                          golden_mst.longitude,
                                          pressure=82000,
                                          temperature=11, delta_t=67,
                                          atmos_refract=0.5667,
                                          how='numpy')
    expected_solpos.index = times
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


def test_spa_python_numpy_physical_dst(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.spa_python(times, golden.latitude,
                                          golden.longitude,
                                          pressure=82000,
                                          temperature=11, delta_t=67,
                                          atmos_refract=0.5667,
                                          how='numpy')
    expected_solpos.index = times
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


@pytest.mark.parametrize('delta_t', [65.0, None, np.array([65, 65])])
def test_sun_rise_set_transit_spa(expected_rise_set_spa, golden, delta_t):
    # solution from NREL SAP web calculator
    south = Location(-35.0, 0.0, tz='UTC')
    times = pd.DatetimeIndex([datetime.datetime(1996, 7, 5, 0),
                              datetime.datetime(2004, 12, 4, 0)]
                             ).tz_localize('UTC')
    sunrise = pd.DatetimeIndex([datetime.datetime(1996, 7, 5, 7, 8, 15),
                                datetime.datetime(2004, 12, 4, 4, 38, 57)]
                               ).tz_localize('UTC').tolist()
    sunset = pd.DatetimeIndex([datetime.datetime(1996, 7, 5, 17, 1, 4),
                               datetime.datetime(2004, 12, 4, 19, 2, 3)]
                              ).tz_localize('UTC').tolist()
    transit = pd.DatetimeIndex([datetime.datetime(1996, 7, 5, 12, 4, 36),
                                datetime.datetime(2004, 12, 4, 11, 50, 22)]
                               ).tz_localize('UTC').tolist()
    frame = pd.DataFrame({'sunrise': sunrise,
                          'sunset': sunset,
                          'transit': transit}, index=times)

    result = solarposition.sun_rise_set_transit_spa(times, south.latitude,
                                                    south.longitude,
                                                    delta_t=delta_t)
    result_rounded = pd.DataFrame(index=result.index)
    # need to iterate because to_datetime does not accept 2D data
    # the rounding fails on pandas < 0.17
    for col, data in result.items():
        result_rounded[col] = data.dt.round('1s')

    assert_frame_equal(frame, result_rounded)

    # test for Golden, CO compare to NREL SPA
    result = solarposition.sun_rise_set_transit_spa(
        expected_rise_set_spa.index, golden.latitude, golden.longitude,
        delta_t=delta_t)

    # round to nearest minute
    result_rounded = pd.DataFrame(index=result.index)
    # need to iterate because to_datetime does not accept 2D data
    for col, data in result.items():
        result_rounded[col] = data.dt.round('s').tz_convert('MST')

    assert_frame_equal(expected_rise_set_spa, result_rounded)


@fail_on_pvlib_version("0.12")
def test_sun_rise_set_transit_spa_renamed_kwarg_warning():
    # test to remember to remove renamed_kwarg_warning after the grace period
    # and modify docs as needed
    pass


@requires_ephem
def test_sun_rise_set_transit_ephem(expected_rise_set_ephem, golden):
    # test for Golden, CO compare to USNO, using local midnight
    result = solarposition.sun_rise_set_transit_ephem(
        expected_rise_set_ephem.index, golden.latitude, golden.longitude,
        next_or_previous='next', altitude=golden.altitude, pressure=0,
        temperature=11, horizon='-0:34')
    # round to nearest minute
    result_rounded = pd.DataFrame(index=result.index)
    for col, data in result.items():
        result_rounded[col] = data.dt.round('min').tz_convert('MST')
    assert_frame_equal(expected_rise_set_ephem, result_rounded)

    # test next sunrise/sunset with times
    times = pd.DatetimeIndex([datetime.datetime(2015, 1, 2, 3, 0, 0),
                              datetime.datetime(2015, 1, 2, 10, 15, 0),
                              datetime.datetime(2015, 1, 2, 15, 3, 0),
                              datetime.datetime(2015, 1, 2, 21, 6, 7)
                              ]).tz_localize('MST')
    expected = pd.DataFrame(index=times,
                            columns=['sunrise', 'sunset'],
                            dtype='datetime64[ns]')
    idx_sunrise = pd.to_datetime(['2015-01-02', '2015-01-03', '2015-01-03',
                                  '2015-01-03']).tz_localize('MST')
    expected['sunrise'] = \
        expected_rise_set_ephem.loc[idx_sunrise, 'sunrise'].tolist()
    idx_sunset = pd.to_datetime(['2015-01-02', '2015-01-02', '2015-01-02',
                                 '2015-01-03']).tz_localize('MST')
    expected['sunset'] = \
        expected_rise_set_ephem.loc[idx_sunset, 'sunset'].tolist()
    idx_transit = pd.to_datetime(['2015-01-02', '2015-01-02', '2015-01-03',
                                  '2015-01-03']).tz_localize('MST')
    expected['transit'] = \
        expected_rise_set_ephem.loc[idx_transit, 'transit'].tolist()

    result = solarposition.sun_rise_set_transit_ephem(times,
                                                      golden.latitude,
                                                      golden.longitude,
                                                      next_or_previous='next',
                                                      altitude=golden.altitude,
                                                      pressure=0,
                                                      temperature=11,
                                                      horizon='-0:34')
    # round to nearest minute
    result_rounded = pd.DataFrame(index=result.index)
    for col, data in result.items():
        result_rounded[col] = data.dt.round('min').tz_convert('MST')
    assert_frame_equal(expected, result_rounded)

    # test previous sunrise/sunset with times
    times = pd.DatetimeIndex([datetime.datetime(2015, 1, 2, 3, 0, 0),
                              datetime.datetime(2015, 1, 2, 10, 15, 0),
                              datetime.datetime(2015, 1, 3, 3, 0, 0),
                              datetime.datetime(2015, 1, 3, 13, 6, 7)
                              ]).tz_localize('MST')
    expected = pd.DataFrame(index=times,
                            columns=['sunrise', 'sunset'],
                            dtype='datetime64[ns]')
    idx_sunrise = pd.to_datetime(['2015-01-01', '2015-01-02', '2015-01-02',
                                  '2015-01-03']).tz_localize('MST')
    expected['sunrise'] = \
        expected_rise_set_ephem.loc[idx_sunrise, 'sunrise'].tolist()
    idx_sunset = pd.to_datetime(['2015-01-01', '2015-01-01', '2015-01-02',
                                 '2015-01-02']).tz_localize('MST')
    expected['sunset'] = \
        expected_rise_set_ephem.loc[idx_sunset, 'sunset'].tolist()
    idx_transit = pd.to_datetime(['2015-01-01', '2015-01-01', '2015-01-02',
                                  '2015-01-03']).tz_localize('MST')
    expected['transit'] = \
        expected_rise_set_ephem.loc[idx_transit, 'transit'].tolist()

    result = solarposition.sun_rise_set_transit_ephem(
        times,
        golden.latitude, golden.longitude, next_or_previous='previous',
        altitude=golden.altitude, pressure=0, temperature=11, horizon='-0:34')
    # round to nearest minute
    result_rounded = pd.DataFrame(index=result.index)
    for col, data in result.items():
        result_rounded[col] = data.dt.round('min').tz_convert('MST')
    assert_frame_equal(expected, result_rounded)

    # test with different timezone
    times = times.tz_convert('UTC')
    expected = expected.tz_convert('UTC')  # resuse result from previous
    for col, data in expected.items():
        expected[col] = data.dt.tz_convert('UTC')
    result = solarposition.sun_rise_set_transit_ephem(
        times,
        golden.latitude, golden.longitude, next_or_previous='previous',
        altitude=golden.altitude, pressure=0, temperature=11, horizon='-0:34')
    # round to nearest minute
    result_rounded = pd.DataFrame(index=result.index)
    for col, data in result.items():
        result_rounded[col] = data.dt.round('min').tz_convert(times.tz)
    assert_frame_equal(expected, result_rounded)


@requires_ephem
def test_sun_rise_set_transit_ephem_error(expected_rise_set_ephem, golden):
    with pytest.raises(ValueError):
        solarposition.sun_rise_set_transit_ephem(expected_rise_set_ephem.index,
                                                 golden.latitude,
                                                 golden.longitude,
                                                 next_or_previous='other')
    tz_naive = pd.DatetimeIndex([datetime.datetime(2015, 1, 2, 3, 0, 0)])
    with pytest.raises(ValueError):
        solarposition.sun_rise_set_transit_ephem(tz_naive,
                                                 golden.latitude,
                                                 golden.longitude,
                                                 next_or_previous='next')


@requires_ephem
def test_sun_rise_set_transit_ephem_horizon(golden):
    times = pd.DatetimeIndex([datetime.datetime(2016, 1, 3, 0, 0, 0)
                              ]).tz_localize('MST')
    # center of sun disk
    center = solarposition.sun_rise_set_transit_ephem(
        times,
        latitude=golden.latitude, longitude=golden.longitude)
    edge = solarposition.sun_rise_set_transit_ephem(
        times,
        latitude=golden.latitude, longitude=golden.longitude, horizon='-0:34')
    result_rounded = (edge['sunrise'] - center['sunrise']).dt.round('min')

    sunrise_delta = datetime.datetime(2016, 1, 3, 7, 17, 11) - \
        datetime.datetime(2016, 1, 3, 7, 21, 33)
    expected = pd.Series(index=times,
                         data=[sunrise_delta],
                         name='sunrise').dt.round('min')
    assert_series_equal(expected, result_rounded)


@requires_ephem
def test_pyephem_physical(expected_solpos, golden_mst):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 12, 30, 30),
                          periods=1, freq='D', tz=golden_mst.tz)
    ephem_data = solarposition.pyephem(times, golden_mst.latitude,
                                       golden_mst.longitude, pressure=82000,
                                       temperature=11)
    expected_solpos.index = times
    assert_frame_equal(expected_solpos.round(2),
                       ephem_data[expected_solpos.columns].round(2))


@requires_ephem
def test_pyephem_physical_dst(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.pyephem(times, golden.latitude,
                                       golden.longitude, pressure=82000,
                                       temperature=11)
    expected_solpos.index = times
    assert_frame_equal(expected_solpos.round(2),
                       ephem_data[expected_solpos.columns].round(2))


@requires_ephem
def test_calc_time():
    import pytz
    import math
    # validation from USNO solar position calculator online

    epoch = datetime.datetime(1970, 1, 1)
    epoch_dt = pytz.utc.localize(epoch)

    loc = tus
    loc.pressure = 0
    actual_time = pytz.timezone(loc.tz).localize(
        datetime.datetime(2014, 10, 10, 8, 30))
    lb = pytz.timezone(loc.tz).localize(datetime.datetime(2014, 10, 10, tol))
    ub = pytz.timezone(loc.tz).localize(datetime.datetime(2014, 10, 10, 10))
    alt = solarposition.calc_time(lb, ub, loc.latitude, loc.longitude,
                                  'alt', math.radians(24.7))
    az = solarposition.calc_time(lb, ub, loc.latitude, loc.longitude,
                                 'az', math.radians(116.3))
    actual_timestamp = (actual_time - epoch_dt).total_seconds()

    assert_allclose((alt.replace(second=0, microsecond=0) -
                     epoch_dt).total_seconds(), actual_timestamp)
    assert_allclose((az.replace(second=0, microsecond=0) -
                     epoch_dt).total_seconds(), actual_timestamp)


@requires_ephem
def test_earthsun_distance():
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D')
    distance = solarposition.pyephem_earthsun_distance(times).values[0]
    assert_allclose(1, distance, atol=0.1)


def test_ephemeris_physical(expected_solpos, golden_mst):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 12, 30, 30),
                          periods=1, freq='D', tz=golden_mst.tz)
    ephem_data = solarposition.ephemeris(times, golden_mst.latitude,
                                         golden_mst.longitude,
                                         pressure=82000,
                                         temperature=11)
    expected_solpos.index = times
    expected_solpos = np.round(expected_solpos, 2)
    ephem_data = np.round(ephem_data, 2)
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


def test_ephemeris_physical_dst(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.ephemeris(times, golden.latitude,
                                         golden.longitude, pressure=82000,
                                         temperature=11)
    expected_solpos.index = times
    expected_solpos = np.round(expected_solpos, 2)
    ephem_data = np.round(ephem_data, 2)
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


def test_ephemeris_physical_no_tz(expected_solpos, golden_mst):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 19, 30, 30),
                          periods=1, freq='D')
    ephem_data = solarposition.ephemeris(times, golden_mst.latitude,
                                         golden_mst.longitude,
                                         pressure=82000,
                                         temperature=11)
    expected_solpos.index = times
    expected_solpos = np.round(expected_solpos, 2)
    ephem_data = np.round(ephem_data, 2)
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


def test_get_solarposition_error(golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    with pytest.raises(ValueError):
        solarposition.get_solarposition(times, golden.latitude,
                                        golden.longitude,
                                        pressure=82000,
                                        temperature=11,
                                        method='error this')


@pytest.mark.parametrize("pressure, expected", [
    (82000, 'expected_solpos'),
    (90000, pd.DataFrame(
        np.array([[39.88997,   50.11003,  194.34024,   39.87205,   14.64151,
                   50.12795]]),
        columns=['apparent_elevation', 'apparent_zenith', 'azimuth',
                 'elevation', 'equation_of_time', 'zenith'],
        index=['2003-10-17T12:30:30Z']))
    ])
def test_get_solarposition_pressure(
        pressure, expected, golden, expected_solpos):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.get_solarposition(times, golden.latitude,
                                                 golden.longitude,
                                                 pressure=pressure,
                                                 temperature=11)
    if isinstance(expected, str) and expected == 'expected_solpos':
        expected = expected_solpos
    this_expected = expected.copy()
    this_expected.index = times
    this_expected = np.round(this_expected, 5)
    ephem_data = np.round(ephem_data, 5)
    assert_frame_equal(this_expected, ephem_data[this_expected.columns])


@pytest.mark.parametrize("altitude, expected", [
    (1830.14, 'expected_solpos'),
    (2000, pd.DataFrame(
        np.array([[39.88788,   50.11212,  194.34024,   39.87205,   14.64151,
                   50.12795]]),
        columns=['apparent_elevation', 'apparent_zenith', 'azimuth',
                 'elevation', 'equation_of_time', 'zenith'],
        index=['2003-10-17T12:30:30Z']))
    ])
def test_get_solarposition_altitude(
        altitude, expected, golden, expected_solpos):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.get_solarposition(times, golden.latitude,
                                                 golden.longitude,
                                                 altitude=altitude,
                                                 temperature=11)
    if isinstance(expected, str) and expected == 'expected_solpos':
        expected = expected_solpos
    this_expected = expected.copy()
    this_expected.index = times
    this_expected = np.round(this_expected, 5)
    ephem_data = np.round(ephem_data, 5)
    assert_frame_equal(this_expected, ephem_data[this_expected.columns])


@pytest.mark.parametrize("delta_t, method", [
    (None, 'nrel_numba'),
    (67.0, 'nrel_numba'),
    (np.array([67.0, 67.0]), 'nrel_numba'),
    # minimize reloads, with numpy being last
    (None, 'nrel_numpy'),
    (67.0, 'nrel_numpy'),
    (np.array([67.0, 67.0]), 'nrel_numpy'),
])
def test_get_solarposition_deltat(delta_t, method, expected_solpos_multi,
                                  golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=2, freq='D', tz=golden.tz)
    with warnings.catch_warnings():
        # don't warn on method reload
        warnings.simplefilter("ignore")
        ephem_data = solarposition.get_solarposition(times, golden.latitude,
                                                     golden.longitude,
                                                     pressure=82000,
                                                     delta_t=delta_t,
                                                     temperature=11,
                                                     method=method)
    this_expected = expected_solpos_multi
    this_expected.index = times
    this_expected = np.round(this_expected, 5)
    ephem_data = np.round(ephem_data, 5)
    assert_frame_equal(this_expected, ephem_data[this_expected.columns])


@pytest.mark.parametrize("method", ['nrel_numba', 'nrel_numpy'])
def test_spa_array_delta_t(method):
    # make sure that time-varying delta_t produces different answers
    times = pd.to_datetime(["2019-01-01", "2019-01-01"]).tz_localize("UTC")
    expected = pd.Series([257.26969492, 257.2701359], index=times)
    with warnings.catch_warnings():
        # don't warn on method reload
        warnings.simplefilter("ignore")
        ephem_data = solarposition.get_solarposition(times, 40, -80,
                                                     delta_t=np.array([67, 0]),
                                                     method=method)

    assert_series_equal(ephem_data['azimuth'], expected, check_names=False)


def test_get_solarposition_no_kwargs(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.get_solarposition(times, golden.latitude,
                                                 golden.longitude)
    expected_solpos.index = times
    expected_solpos = np.round(expected_solpos, 2)
    ephem_data = np.round(ephem_data, 2)
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


@requires_ephem
def test_get_solarposition_method_pyephem(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)
    ephem_data = solarposition.get_solarposition(times, golden.latitude,
                                                 golden.longitude,
                                                 method='pyephem')
    expected_solpos.index = times
    expected_solpos = np.round(expected_solpos, 2)
    ephem_data = np.round(ephem_data, 2)
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


@pytest.mark.parametrize('delta_t', [64.0, None, np.array([64, 64])])
def test_nrel_earthsun_distance(delta_t):
    times = pd.DatetimeIndex([datetime.datetime(2015, 1, 2),
                              datetime.datetime(2015, 8, 2)]
                             ).tz_localize('MST')
    result = solarposition.nrel_earthsun_distance(times, delta_t=delta_t)
    expected = pd.Series(np.array([0.983289204601, 1.01486146446]),
                         index=times)
    assert_series_equal(expected, result)

    if np.size(delta_t) == 1:  # skip the array delta_t
        times = datetime.datetime(2015, 1, 2)
        result = solarposition.nrel_earthsun_distance(times, delta_t=delta_t)
        expected = pd.Series(np.array([0.983289204601]),
                             index=pd.DatetimeIndex([times, ]))
        assert_series_equal(expected, result)


def test_equation_of_time():
    times = pd.date_range(start="1/1/2015 0:00", end="12/31/2015 23:00",
                          freq="h")
    output = solarposition.spa_python(times, 37.8, -122.25, 100)
    eot = output['equation_of_time']
    eot_rng = eot.max() - eot.min()  # range of values, around 30 minutes
    eot_1 = solarposition.equation_of_time_spencer71(times.dayofyear)
    eot_2 = solarposition.equation_of_time_pvcdrom(times.dayofyear)
    assert np.allclose(eot_1 / eot_rng, eot / eot_rng, atol=0.3)  # spencer
    assert np.allclose(eot_2 / eot_rng, eot / eot_rng, atol=0.4)  # pvcdrom


def test_declination():
    times = pd.date_range(start="1/1/2015 0:00", end="12/31/2015 23:00",
                          freq="h")
    atmos_refract = 0.5667
    delta_t = spa.calculate_deltat(times.year, times.month)
    unixtime = np.array([calendar.timegm(t.timetuple()) for t in times])
    _, _, declination = spa.solar_position(unixtime, 37.8, -122.25, 100,
                                           1013.25, 25, delta_t, atmos_refract,
                                           sst=True)
    declination = np.deg2rad(declination)
    declination_rng = declination.max() - declination.min()
    declination_1 = solarposition.declination_cooper69(times.dayofyear)
    declination_2 = solarposition.declination_spencer71(times.dayofyear)
    a, b = declination_1 / declination_rng, declination / declination_rng
    assert np.allclose(a, b, atol=0.03)  # cooper
    a, b = declination_2 / declination_rng, declination / declination_rng
    assert np.allclose(a, b, atol=0.02)  # spencer


def test_analytical_zenith():
    times = pd.date_range(start="1/1/2015 0:00", end="12/31/2015 23:00",
                          freq="h").tz_localize('Etc/GMT+8')
    times_utc = times.tz_convert('UTC')
    lat, lon = 37.8, -122.25
    lat_rad = np.deg2rad(lat)
    output = solarposition.spa_python(times, lat, lon, 100)
    solar_zenith = np.deg2rad(output['zenith'])  # spa
    # spencer
    eot = solarposition.equation_of_time_spencer71(times_utc.dayofyear)
    hour_angle = np.deg2rad(solarposition.hour_angle(times, lon, eot))
    decl = solarposition.declination_spencer71(times_utc.dayofyear)
    zenith_1 = solarposition.solar_zenith_analytical(lat_rad, hour_angle, decl)
    # pvcdrom and cooper
    eot = solarposition.equation_of_time_pvcdrom(times_utc.dayofyear)
    hour_angle = np.deg2rad(solarposition.hour_angle(times, lon, eot))
    decl = solarposition.declination_cooper69(times_utc.dayofyear)
    zenith_2 = solarposition.solar_zenith_analytical(lat_rad, hour_angle, decl)
    assert np.allclose(zenith_1, solar_zenith, atol=0.015)
    assert np.allclose(zenith_2, solar_zenith, atol=0.025)


def test_analytical_azimuth():
    times = pd.date_range(start="1/1/2015 0:00", end="12/31/2015 23:00",
                          freq="h").tz_localize('Etc/GMT+8')
    times_utc = times.tz_convert('UTC')
    lat, lon = 37.8, -122.25
    lat_rad = np.deg2rad(lat)
    output = solarposition.spa_python(times, lat, lon, 100)
    solar_azimuth = np.deg2rad(output['azimuth'])  # spa
    solar_zenith = np.deg2rad(output['zenith'])
    # spencer
    eot = solarposition.equation_of_time_spencer71(times_utc.dayofyear)
    hour_angle = np.deg2rad(solarposition.hour_angle(times, lon, eot))
    decl = solarposition.declination_spencer71(times_utc.dayofyear)
    zenith = solarposition.solar_zenith_analytical(lat_rad, hour_angle, decl)
    azimuth_1 = solarposition.solar_azimuth_analytical(lat_rad, hour_angle,
                                                       decl, zenith)
    # pvcdrom and cooper
    eot = solarposition.equation_of_time_pvcdrom(times_utc.dayofyear)
    hour_angle = np.deg2rad(solarposition.hour_angle(times, lon, eot))
    decl = solarposition.declination_cooper69(times_utc.dayofyear)
    zenith = solarposition.solar_zenith_analytical(lat_rad, hour_angle, decl)
    azimuth_2 = solarposition.solar_azimuth_analytical(lat_rad, hour_angle,
                                                       decl, zenith)

    idx = np.where(solar_zenith < np.pi/2)
    assert np.allclose(azimuth_1[idx], solar_azimuth.values[idx], atol=0.01)
    assert np.allclose(azimuth_2[idx], solar_azimuth.values[idx], atol=0.017)

    # test for NaN values at boundary conditions (PR #431)
    test_angles = np.radians(np.array(
                   [[   0., -180.,  -20.],
                    [   0.,    0.,   -5.],
                    [   0.,    0.,    0.],
                    [   0.,    0.,   15.],
                    [   0.,  180.,   20.],
                    [  30.,    0.,  -20.],
                    [  30.,    0.,   -5.],
                    [  30.,    0.,    0.],
                    [  30.,  180.,    5.],
                    [  30.,    0.,   10.],
                    [ -30.,    0.,  -20.],
                    [ -30.,    0.,  -15.],
                    [ -30.,    0.,    0.],
                    [ -30., -180.,    5.],
                    [ -30.,  180.,   10.]]))

    zeniths = solarposition.solar_zenith_analytical(*test_angles.T)
    azimuths = solarposition.solar_azimuth_analytical(*test_angles.T,
                                                      zenith=zeniths)

    assert not np.isnan(azimuths).any()


def test_hour_angle():
    """
    Test conversion from hours to hour angles in degrees given the following
    inputs from NREL SPA calculator at Golden, CO
    date,times,eot,sunrise,sunset
    1/2/2015,7:21:55,-3.935172,-70.699400,70.512721
    1/2/2015,16:47:43,-4.117227,-70.699400,70.512721
    1/2/2015,12:04:45,-4.026295,-70.699400,70.512721
    """
    longitude = -105.1786  # degrees
    times = pd.DatetimeIndex([
        '2015-01-02 07:21:55.2132',
        '2015-01-02 16:47:42.9828',
        '2015-01-02 12:04:44.6340'
    ]).tz_localize('Etc/GMT+7')
    eot = np.array([-3.935172, -4.117227, -4.026295])
    hourangle = solarposition.hour_angle(times, longitude, eot)
    expected = (-70.682338, 70.72118825000001, 0.000801250)
    # FIXME: there are differences from expected NREL SPA calculator values
    # sunrise: 4 seconds, sunset: 48 seconds, transit: 0.2 seconds
    # but the differences may be due to other SPA input parameters
    assert np.allclose(hourangle, expected)

    hours = solarposition._hour_angle_to_hours(
        times, hourangle, longitude, eot)
    result = solarposition._times_to_hours_after_local_midnight(times)
    assert np.allclose(result, hours)

    result = solarposition._local_times_from_hours_since_midnight(times, hours)
    assert result.equals(times)

    times = times.tz_convert(None)
    with pytest.raises(ValueError):
        solarposition.hour_angle(times, longitude, eot)
    with pytest.raises(ValueError):
        solarposition._hour_angle_to_hours(times, hourangle, longitude, eot)
    with pytest.raises(ValueError):
        solarposition._times_to_hours_after_local_midnight(times)
    with pytest.raises(ValueError):
        solarposition._local_times_from_hours_since_midnight(times, hours)


@fail_on_pvlib_version('0.12')
def test_hour_angle_renamed_kwarg_warning():
    # test to remember to remove renamed_kwarg_warning after the grace period
    pass


def test_sun_rise_set_transit_geometric(expected_rise_set_spa, golden_mst):
    """Test geometric calculations for sunrise, sunset, and transit times"""
    times = expected_rise_set_spa.index
    times_utc = times.tz_convert('UTC')
    latitude = golden_mst.latitude
    longitude = golden_mst.longitude
    eot = solarposition.equation_of_time_spencer71(
        times_utc.dayofyear)  # minutes
    decl = solarposition.declination_spencer71(times_utc.dayofyear)  # radians
    with pytest.raises(ValueError):
        solarposition.sun_rise_set_transit_geometric(
            times.tz_convert(None), latitude=latitude, longitude=longitude,
            declination=decl, equation_of_time=eot)
    sr, ss, st = solarposition.sun_rise_set_transit_geometric(
        times, latitude=latitude, longitude=longitude, declination=decl,
        equation_of_time=eot)
    # sunrise: 2015-01-02 07:26:39.763224487, 2015-08-02 05:04:35.688533801
    # sunset:  2015-01-02 16:41:29.951096777, 2015-08-02 19:09:46.597355085
    # transit: 2015-01-02 12:04:04.857160632, 2015-08-02 12:07:11.142944443
    test_sunrise = solarposition._times_to_hours_after_local_midnight(sr)
    test_sunset = solarposition._times_to_hours_after_local_midnight(ss)
    test_transit = solarposition._times_to_hours_after_local_midnight(st)
    # convert expected SPA sunrise, sunset, transit to local datetime indices
    expected_sunrise = pd.DatetimeIndex(expected_rise_set_spa.sunrise.values,
                                        tz='UTC').tz_convert(golden_mst.tz)
    expected_sunset = pd.DatetimeIndex(expected_rise_set_spa.sunset.values,
                                       tz='UTC').tz_convert(golden_mst.tz)
    expected_transit = pd.DatetimeIndex(expected_rise_set_spa.transit.values,
                                        tz='UTC').tz_convert(golden_mst.tz)
    # convert expected times to hours since midnight as arrays of floats
    expected_sunrise = solarposition._times_to_hours_after_local_midnight(
        expected_sunrise)
    expected_sunset = solarposition._times_to_hours_after_local_midnight(
        expected_sunset)
    expected_transit = solarposition._times_to_hours_after_local_midnight(
        expected_transit)
    # geometric time has about 4-6 minute error compared to SPA sunset/sunrise
    expected_sunrise_error = np.array(
        [0.07910089555555544, 0.06908014805555496])  # 4.8[min], 4.2[min]
    expected_sunset_error = np.array(
        [-0.1036246955555562, -0.06983406805555603])  # -6.2[min], -4.2[min]
    expected_transit_error = np.array(
        [-0.011150788888889096, 0.0036508177777765383])  # -40[sec], 13.3[sec]
    assert np.allclose(test_sunrise, expected_sunrise,
                       atol=np.abs(expected_sunrise_error).max())
    assert np.allclose(test_sunset, expected_sunset,
                       atol=np.abs(expected_sunset_error).max())
    assert np.allclose(test_transit, expected_transit,
                       atol=np.abs(expected_transit_error).max())


@pytest.mark.parametrize('tz', [None, 'utc', 'US/Eastern'])
def test__datetime_to_unixtime(tz):
    # for pandas < 2.0 where "unit" doesn't exist in pd.date_range. note that
    # unit of ns is the only option in pandas<2, and the default in pandas 2.x
    times = pd.date_range(start='2019-01-01', freq='h', periods=3, tz=tz)
    expected = times.view(np.int64)/10**9
    actual = solarposition._datetime_to_unixtime(times)
    np.testing.assert_equal(expected, actual)


@requires_pandas_2_0
@pytest.mark.parametrize('unit', ['ns', 'us', 's'])
@pytest.mark.parametrize('tz', [None, 'utc', 'US/Eastern'])
def test__datetime_to_unixtime_units(unit, tz):
    kwargs = dict(start='2019-01-01', freq='h', periods=3)
    times = pd.date_range(**kwargs, unit='ns', tz='UTC')
    expected = times.view(np.int64)/10**9

    times = pd.date_range(**kwargs, unit=unit, tz='UTC').tz_convert(tz)
    actual = solarposition._datetime_to_unixtime(times)
    np.testing.assert_equal(expected, actual)


@requires_pandas_2_0
@pytest.mark.parametrize('tz', [None, 'utc', 'US/Eastern'])
@pytest.mark.parametrize('method', [
    'nrel_numpy',
    'ephemeris',
    pytest.param('pyephem', marks=requires_ephem),
    pytest.param('nrel_numba', marks=requires_numba),
    pytest.param('nrel_c', marks=requires_spa_c),
])
def test_get_solarposition_microsecond_index(method, tz):
    # https://github.com/pvlib/pvlib-python/issues/1932

    kwargs = dict(start='2019-01-01', freq='h', periods=24, tz=tz)

    index_ns = pd.date_range(unit='ns', **kwargs)
    index_us = pd.date_range(unit='us', **kwargs)

    with warnings.catch_warnings():
        # don't warn on method reload
        warnings.simplefilter("ignore")

        sp_ns = solarposition.get_solarposition(index_ns, 0, 0, method=method)
        sp_us = solarposition.get_solarposition(index_us, 0, 0, method=method)

    assert_frame_equal(sp_ns, sp_us, check_index_type=False)


@requires_pandas_2_0
@pytest.mark.parametrize('tz', [None, 'utc', 'US/Eastern'])
def test_nrel_earthsun_distance_microsecond_index(tz):
    # https://github.com/pvlib/pvlib-python/issues/1932

    kwargs = dict(start='2019-01-01', freq='h', periods=24, tz=tz)

    index_ns = pd.date_range(unit='ns', **kwargs)
    index_us = pd.date_range(unit='us', **kwargs)

    esd_ns = solarposition.nrel_earthsun_distance(index_ns)
    esd_us = solarposition.nrel_earthsun_distance(index_us)

    assert_series_equal(esd_ns, esd_us, check_index_type=False)


@requires_pandas_2_0
@pytest.mark.parametrize('tz', ['utc', 'US/Eastern'])
def test_hour_angle_microsecond_index(tz):
    # https://github.com/pvlib/pvlib-python/issues/1932

    kwargs = dict(start='2019-01-01', freq='h', periods=24, tz=tz)

    index_ns = pd.date_range(unit='ns', **kwargs)
    index_us = pd.date_range(unit='us', **kwargs)

    ha_ns = solarposition.hour_angle(index_ns, -80, 0)
    ha_us = solarposition.hour_angle(index_us, -80, 0)

    np.testing.assert_equal(ha_ns, ha_us)


@requires_pandas_2_0
@pytest.mark.parametrize('tz', ['utc', 'US/Eastern'])
def test_rise_set_transit_spa_microsecond_index(tz):
    # https://github.com/pvlib/pvlib-python/issues/1932

    kwargs = dict(start='2019-01-01', freq='h', periods=24, tz=tz)

    index_ns = pd.date_range(unit='ns', **kwargs)
    index_us = pd.date_range(unit='us', **kwargs)

    rst_ns = solarposition.sun_rise_set_transit_spa(index_ns, 40, -80)
    rst_us = solarposition.sun_rise_set_transit_spa(index_us, 40, -80)

    assert_frame_equal(rst_ns, rst_us, check_index_type=False)


@requires_pandas_2_0
@pytest.mark.parametrize('tz', ['utc', 'US/Eastern'])
def test_rise_set_transit_geometric_microsecond_index(tz):
    # https://github.com/pvlib/pvlib-python/issues/1932

    kwargs = dict(start='2019-01-01', freq='h', periods=24, tz=tz)

    index_ns = pd.date_range(unit='ns', **kwargs)
    index_us = pd.date_range(unit='us', **kwargs)

    args = (40, -80, 0, 0)
    rst_ns = solarposition.sun_rise_set_transit_geometric(index_ns, *args)
    rst_us = solarposition.sun_rise_set_transit_geometric(index_us, *args)

    for times_ns, times_us in zip(rst_ns, rst_us):
        # can't use a fancy assert function here since the units are different
        assert all(times_ns == times_us)


# put numba tests at end of file to minimize reloading

@requires_numba
def test_spa_python_numba_physical(expected_solpos, golden_mst):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 12, 30, 30),
                          periods=1, freq='D', tz=golden_mst.tz)
    with warnings.catch_warnings():
        # don't warn on method reload
        # ensure that numpy is the most recently used method so that
        # we can use the warns filter below
        warnings.simplefilter("ignore")
        ephem_data = solarposition.spa_python(times, golden_mst.latitude,
                                              golden_mst.longitude,
                                              pressure=82000,
                                              temperature=11, delta_t=67,
                                              atmos_refract=0.5667,
                                              how='numpy', numthreads=1)
    with pytest.warns(UserWarning):
        ephem_data = solarposition.spa_python(times, golden_mst.latitude,
                                              golden_mst.longitude,
                                              pressure=82000,
                                              temperature=11, delta_t=67,
                                              atmos_refract=0.5667,
                                              how='numba', numthreads=1)
    expected_solpos.index = times
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])


@requires_numba
def test_spa_python_numba_physical_dst(expected_solpos, golden):
    times = pd.date_range(datetime.datetime(2003, 10, 17, 13, 30, 30),
                          periods=1, freq='D', tz=golden.tz)

    with warnings.catch_warnings():
        # don't warn on method reload
        warnings.simplefilter("ignore")
        ephem_data = solarposition.spa_python(times, golden.latitude,
                                              golden.longitude, pressure=82000,
                                              temperature=11, delta_t=67,
                                              atmos_refract=0.5667,
                                              how='numba', numthreads=1)
    expected_solpos.index = times
    assert_frame_equal(expected_solpos, ephem_data[expected_solpos.columns])

    with pytest.warns(UserWarning):
        # test that we get a warning when reloading to use numpy only
        ephem_data = solarposition.spa_python(times, golden.latitude,
                                              golden.longitude,
                                              pressure=82000,
                                              temperature=11, delta_t=67,
                                              atmos_refract=0.5667,
                                              how='numpy', numthreads=1)