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#!/usr/bin/env python
import unittest
# Determine whether the equinoxes and solstices which PyEphem predicts
# fall within one minute (by the clock) of those predicted by the
# United States Naval Observatory.
# Data is from http://aa.usno.navy.mil/data/docs/EarthSeasons.php
usno_data = """
d h d h m d h m
2000 2000
Perihelion Jan 3 05 Equinoxes Mar 20 07 35 Sept 22 17 27
Aphelion July 4 00 Solstices June 21 01 48 Dec 21 13 37
2001 2001
Perihelion Jan 4 09 Equinoxes Mar 20 13 31 Sept 22 23 04
Aphelion July 4 14 Solstices June 21 07 38 Dec 21 19 21
2002 2002
Perihelion Jan 2 14 Equinoxes Mar 20 19 16 Sept 23 04 55
Aphelion July 6 04 Solstices June 21 13 24 Dec 22 01 14
2003 2003
Perihelion Jan 4 05 Equinoxes Mar 21 01 00 Sept 23 10 47
Aphelion July 4 06 Solstices June 21 19 10 Dec 22 07 04
2004 2004
Perihelion Jan 4 18 Equinoxes Mar 20 06 49 Sept 22 16 30
Aphelion July 5 11 Solstices June 21 00 57 Dec 21 12 42
2005 2005
Perihelion Jan 2 01 Equinoxes Mar 20 12 33 Sept 22 22 23
Aphelion July 5 05 Solstices June 21 06 46 Dec 21 18 35
2006 2006
Perihelion Jan 4 15 Equinoxes Mar 20 18 26 Sept 23 04 03
Aphelion July 3 23 Solstices June 21 12 26 Dec 22 00 22
2007 2007
Perihelion Jan 3 20 Equinoxes Mar 21 00 07 Sept 23 09 51
Aphelion July 7 00 Solstices June 21 18 06 Dec 22 06 08
2008 2008
Perihelion Jan 3 00 Equinoxes Mar 20 05 48 Sept 22 15 44
Aphelion July 4 08 Solstices June 20 23 59 Dec 21 12 04
2009 2009
Perihelion Jan 4 15 Equinoxes Mar 20 11 44 Sept 22 21 18
Aphelion July 4 02 Solstices June 21 05 45 Dec 21 17 47
2010 2010
Perihelion Jan 3 00 Equinoxes Mar 20 17 32 Sept 23 03 09
Aphelion July 6 11 Solstices June 21 11 28 Dec 21 23 38
2011 2011
Perihelion Jan 3 19 Equinoxes Mar 20 23 21 Sept 23 09 04
Aphelion July 4 15 Solstices June 21 17 16 Dec 22 05 30
2012 2012
Perihelion Jan 5 00 Equinoxes Mar 20 05 14 Sept 22 14 49
Aphelion July 5 03 Solstices June 20 23 09 Dec 21 11 11
2013 2013
Perihelion Jan 2 05 Equinoxes Mar 20 11 02 Sept 22 20 44
Aphelion July 5 15 Solstices June 21 05 04 Dec 21 17 11
2014 2014
Perihelion Jan 4 12 Equinoxes Mar 20 16 57 Sept 23 02 29
Aphelion July 4 00 Solstices June 21 10 51 Dec 21 23 03
2015 2015
Perihelion Jan 4 07 Equinoxes Mar 20 22 45 Sept 23 08 20
Aphelion July 6 19 Solstices June 21 16 38 Dec 22 04 48
2016 2016
Perihelion Jan 2 23 Equinoxes Mar 20 04 30 Sept 22 14 21
Aphelion July 4 16 Solstices June 20 22 34 Dec 21 10 44
2017 2017
Perihelion Jan 4 14 Equinoxes Mar 20 10 28 Sept 22 20 02
Aphelion July 3 20 Solstices June 21 04 24 Dec 21 16 28
2018 2018
Perihelion Jan 3 06 Equinoxes Mar 20 16 15 Sept 23 01 54
Aphelion July 6 17 Solstices June 21 10 07 Dec 21 22 22
2019 2019
Perihelion Jan 3 05 Equinoxes Mar 20 21 58 Sept 23 07 50
Aphelion July 4 22 Solstices June 21 15 54 Dec 22 04 19
2020 2020
Perihelion Jan 5 08 Equinoxes Mar 20 03 49 Sept 22 13 30
Aphelion July 4 12 Solstices June 20 21 43 Dec 21 10 02
"""
#
import datetime, time
import ephem
# Since users might be in another locale, we have to translate the
# month into an integer on our own.
month_ints = {
'Jan': 1, 'Feb': 2, 'Mar': 3, 'Apr': 4, 'May': 5, 'Jun': 6,
'Jul': 7, 'Aug': 8, 'Sep': 9, 'Oct': 10, 'Nov': 11, 'Dec': 12,
}
sun = ephem.Sun()
def to_date(year, monthname, day, hour, minute):
mi = month_ints[monthname[:3]]
s = '%s/%s/%s %s:%s' % (year, mi, day, hour, minute)
dt = datetime.datetime(*time.strptime(s, '%Y/%m/%d %H:%M')[0:5])
return ephem.date(dt)
def sequence_of_events(data):
seq = []
for line in data.split('\n'):
fields = line.split()
if line.startswith('2'):
fields = line.split()
year = int(fields[0]) # '2001' or whatever
elif line.startswith('Perihelion'):
seq.append((to_date(year, *fields[5:9]), 'vernal equinox'))
seq.append((to_date(year, *fields[9:13]), 'autumnal equinox'))
elif line.startswith('Aphelion'):
seq.append((to_date(year, *fields[5:9]), 'summer solstice'))
seq.append((to_date(year, *fields[9:13]), 'winter solstice'))
seq.sort()
return seq
def run_test(seq, step, functions):
if step > 0:
date = seq[0][0] - 1 # one day earlier than first event
r = range(0, len(seq))
else:
date = seq[-1][0] + 1 # one day after last event
r = range(len(seq) - 1, -1, -1)
for i in r:
usno_date = seq[i][0]
function = functions[i % len(functions)]
date = function(date)
if abs(usno_date - date) > ephem.minute:
raise AssertionError(
'The USNO predicts a %s at %s but PyEphem at %s'
% (seq[i][1], usno_date, date))
def process_usno(data):
seq = sequence_of_events(data)
run_test(seq, +1, (ephem.next_equinox,
ephem.next_solstice,
ephem.next_equinox,
ephem.next_solstice,
))
run_test(seq, +1, (ephem.next_vernal_equinox,
ephem.next_summer_solstice,
ephem.next_autumnal_equinox,
ephem.next_winter_solstice,
))
run_test(seq, -1, (ephem.previous_equinox,
ephem.previous_solstice,
ephem.previous_equinox,
ephem.previous_solstice,
))
run_test(seq, -1, (ephem.previous_vernal_equinox,
ephem.previous_summer_solstice,
ephem.previous_autumnal_equinox,
ephem.previous_winter_solstice,
))
class UsnoEquinoxesTests(unittest.TestCase):
def test_equinoxes(self):
process_usno(usno_data)
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