laywerrobot/lib/python3.6/site-packages/pandas/tests/scalar/timestamp/test_arithmetic.py
2020-08-27 21:55:39 +02:00

76 lines
2.5 KiB
Python

# -*- coding: utf-8 -*-
from datetime import datetime, timedelta
import pytest
import numpy as np
from pandas.compat import long
from pandas.tseries import offsets
from pandas import Timestamp, Timedelta
class TestTimestampArithmetic(object):
def test_overflow_offset(self):
# xref https://github.com/statsmodels/statsmodels/issues/3374
# ends up multiplying really large numbers which overflow
stamp = Timestamp('2017-01-13 00:00:00', freq='D')
offset = 20169940 * offsets.Day(1)
with pytest.raises(OverflowError):
stamp + offset
with pytest.raises(OverflowError):
offset + stamp
with pytest.raises(OverflowError):
stamp - offset
def test_delta_preserve_nanos(self):
val = Timestamp(long(1337299200000000123))
result = val + timedelta(1)
assert result.nanosecond == val.nanosecond
def test_timestamp_sub_datetime(self):
dt = datetime(2013, 10, 12)
ts = Timestamp(datetime(2013, 10, 13))
assert (ts - dt).days == 1
assert (dt - ts).days == -1
def test_addition_subtraction_types(self):
# Assert on the types resulting from Timestamp +/- various date/time
# objects
dt = datetime(2014, 3, 4)
td = timedelta(seconds=1)
# build a timestamp with a frequency, since then it supports
# addition/subtraction of integers
ts = Timestamp(dt, freq='D')
assert type(ts + 1) == Timestamp
assert type(ts - 1) == Timestamp
# Timestamp + datetime not supported, though subtraction is supported
# and yields timedelta more tests in tseries/base/tests/test_base.py
assert type(ts - dt) == Timedelta
assert type(ts + td) == Timestamp
assert type(ts - td) == Timestamp
# Timestamp +/- datetime64 not supported, so not tested (could possibly
# assert error raised?)
td64 = np.timedelta64(1, 'D')
assert type(ts + td64) == Timestamp
assert type(ts - td64) == Timestamp
def test_addition_subtraction_preserve_frequency(self):
ts = Timestamp('2014-03-05', freq='D')
td = timedelta(days=1)
original_freq = ts.freq
assert (ts + 1).freq == original_freq
assert (ts - 1).freq == original_freq
assert (ts + td).freq == original_freq
assert (ts - td).freq == original_freq
td64 = np.timedelta64(1, 'D')
assert (ts + td64).freq == original_freq
assert (ts - td64).freq == original_freq