test_shiftdata_rounding.py

import numpy as np
from mpl_toolkits.basemap import Basemap

def test_shiftdata_rounding():
    m = Basemap(projection='cyl', llcrnrlon=-180, urcrnrlon=180,
                llcrnrlat=-90, urcrnrlat=90, lon_0=0)

    lonsin = np.array([104.123456789, -75.987654321])
    datain = np.array([1.0, 2.0])

    lonsout, dataout = m.shiftdata(lonsin, datain)

    expected_lons = np.round(lonsin, 6)
    np.testing.assert_allclose(np.sort(lonsout), np.sort(expected_lons), rtol=1e-8, atol=1e-8)
    assert np.array_equal(np.sort(dataout), np.sort(datain))