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''' Tests for netcdf '''
from __future__ import division, print_function, absolute_import
import os
from os.path import join as pjoin, dirname
import shutil
import tempfile
import warnings
from io import BytesIO
from glob import glob
from contextlib import contextmanager
import numpy as np
from numpy.testing import assert_, assert_allclose, assert_equal
from pytest import raises as assert_raises
from scipy.io.netcdf import netcdf_file, IS_PYPY
from scipy._lib._numpy_compat import suppress_warnings
from scipy._lib._tmpdirs import in_tempdir
TEST_DATA_PATH = pjoin(dirname(__file__), 'data')
N_EG_ELS = 11 # number of elements for example variable
VARTYPE_EG = 'b' # var type for example variable
@contextmanager
def make_simple(*args, **kwargs):
f = netcdf_file(*args, **kwargs)
f.history = 'Created for a test'
f.createDimension('time', N_EG_ELS)
time = f.createVariable('time', VARTYPE_EG, ('time',))
time[:] = np.arange(N_EG_ELS)
time.units = 'days since 2008-01-01'
f.flush()
yield f
f.close()
def check_simple(ncfileobj):
'''Example fileobj tests '''
assert_equal(ncfileobj.history, b'Created for a test')
time = ncfileobj.variables['time']
assert_equal(time.units, b'days since 2008-01-01')
assert_equal(time.shape, (N_EG_ELS,))
assert_equal(time[-1], N_EG_ELS-1)
def assert_mask_matches(arr, expected_mask):
'''
Asserts that the mask of arr is effectively the same as expected_mask.
In contrast to numpy.ma.testutils.assert_mask_equal, this function allows
testing the 'mask' of a standard numpy array (the mask in this case is treated
as all False).
Parameters
----------
arr: ndarray or MaskedArray
Array to test.
expected_mask: array_like of booleans
A list giving the expected mask.
'''
mask = np.ma.getmaskarray(arr)
assert_equal(mask, expected_mask)
def test_read_write_files():
# test round trip for example file
cwd = os.getcwd()
try:
tmpdir = tempfile.mkdtemp()
os.chdir(tmpdir)
with make_simple('simple.nc', 'w') as f:
pass
# read the file we just created in 'a' mode
with netcdf_file('simple.nc', 'a') as f:
check_simple(f)
# add something
f._attributes['appendRan'] = 1
# To read the NetCDF file we just created::
with netcdf_file('simple.nc') as f:
# Using mmap is the default (but not on pypy)
assert_equal(f.use_mmap, not IS_PYPY)
check_simple(f)
assert_equal(f._attributes['appendRan'], 1)
# Read it in append (and check mmap is off)
with netcdf_file('simple.nc', 'a') as f:
assert_(not f.use_mmap)
check_simple(f)
assert_equal(f._attributes['appendRan'], 1)
# Now without mmap
with netcdf_file('simple.nc', mmap=False) as f:
# Using mmap is the default
assert_(not f.use_mmap)
check_simple(f)
# To read the NetCDF file we just created, as file object, no
# mmap. When n * n_bytes(var_type) is not divisible by 4, this
# raised an error in pupynere 1.0.12 and scipy rev 5893, because
# calculated vsize was rounding up in units of 4 - see
# https://www.unidata.ucar.edu/software/netcdf/docs/user_guide.html
with open('simple.nc', 'rb') as fobj:
with netcdf_file(fobj) as f:
# by default, don't use mmap for file-like
assert_(not f.use_mmap)
check_simple(f)
# Read file from fileobj, with mmap
with suppress_warnings() as sup:
if IS_PYPY:
sup.filter(RuntimeWarning,
"Cannot close a netcdf_file opened with mmap=True.*")
with open('simple.nc', 'rb') as fobj:
with netcdf_file(fobj, mmap=True) as f:
assert_(f.use_mmap)
check_simple(f)
# Again read it in append mode (adding another att)
with open('simple.nc', 'r+b') as fobj:
with netcdf_file(fobj, 'a') as f:
assert_(not f.use_mmap)
check_simple(f)
f.createDimension('app_dim', 1)
var = f.createVariable('app_var', 'i', ('app_dim',))
var[:] = 42
# And... check that app_var made it in...
with netcdf_file('simple.nc') as f:
check_simple(f)
assert_equal(f.variables['app_var'][:], 42)
except: # noqa: E722
os.chdir(cwd)
shutil.rmtree(tmpdir)
raise
os.chdir(cwd)
shutil.rmtree(tmpdir)
def test_read_write_sio():
eg_sio1 = BytesIO()
with make_simple(eg_sio1, 'w') as f1:
str_val = eg_sio1.getvalue()
eg_sio2 = BytesIO(str_val)
with netcdf_file(eg_sio2) as f2:
check_simple(f2)
# Test that error is raised if attempting mmap for sio
eg_sio3 = BytesIO(str_val)
assert_raises(ValueError, netcdf_file, eg_sio3, 'r', True)
# Test 64-bit offset write / read
eg_sio_64 = BytesIO()
with make_simple(eg_sio_64, 'w', version=2) as f_64:
str_val = eg_sio_64.getvalue()
eg_sio_64 = BytesIO(str_val)
with netcdf_file(eg_sio_64) as f_64:
check_simple(f_64)
assert_equal(f_64.version_byte, 2)
# also when version 2 explicitly specified
eg_sio_64 = BytesIO(str_val)
with netcdf_file(eg_sio_64, version=2) as f_64:
check_simple(f_64)
assert_equal(f_64.version_byte, 2)
def test_bytes():
raw_file = BytesIO()
f = netcdf_file(raw_file, mode='w')
# Dataset only has a single variable, dimension and attribute to avoid
# any ambiguity related to order.
f.a = 'b'
f.createDimension('dim', 1)
var = f.createVariable('var', np.int16, ('dim',))
var[0] = -9999
var.c = 'd'
f.sync()
actual = raw_file.getvalue()
expected = (b'CDF\x01'
b'\x00\x00\x00\x00'
b'\x00\x00\x00\x0a'
b'\x00\x00\x00\x01'
b'\x00\x00\x00\x03'
b'dim\x00'
b'\x00\x00\x00\x01'
b'\x00\x00\x00\x0c'
b'\x00\x00\x00\x01'
b'\x00\x00\x00\x01'
b'a\x00\x00\x00'
b'\x00\x00\x00\x02'
b'\x00\x00\x00\x01'
b'b\x00\x00\x00'
b'\x00\x00\x00\x0b'
b'\x00\x00\x00\x01'
b'\x00\x00\x00\x03'
b'var\x00'
b'\x00\x00\x00\x01'
b'\x00\x00\x00\x00'
b'\x00\x00\x00\x0c'
b'\x00\x00\x00\x01'
b'\x00\x00\x00\x01'
b'c\x00\x00\x00'
b'\x00\x00\x00\x02'
b'\x00\x00\x00\x01'
b'd\x00\x00\x00'
b'\x00\x00\x00\x03'
b'\x00\x00\x00\x04'
b'\x00\x00\x00\x78'
b'\xd8\xf1\x80\x01')
assert_equal(actual, expected)
def test_encoded_fill_value():
with netcdf_file(BytesIO(), mode='w') as f:
f.createDimension('x', 1)
var = f.createVariable('var', 'S1', ('x',))
assert_equal(var._get_encoded_fill_value(), b'\x00')
var._FillValue = b'\x01'
assert_equal(var._get_encoded_fill_value(), b'\x01')
var._FillValue = b'\x00\x00' # invalid, wrong size
assert_equal(var._get_encoded_fill_value(), b'\x00')
def test_read_example_data():
# read any example data files
for fname in glob(pjoin(TEST_DATA_PATH, '*.nc')):
with netcdf_file(fname, 'r') as f:
pass
with netcdf_file(fname, 'r', mmap=False) as f:
pass
def test_itemset_no_segfault_on_readonly():
# Regression test for ticket #1202.
# Open the test file in read-only mode.
filename = pjoin(TEST_DATA_PATH, 'example_1.nc')
with suppress_warnings() as sup:
sup.filter(RuntimeWarning,
"Cannot close a netcdf_file opened with mmap=True, when netcdf_variables or arrays referring to its data still exist")
with netcdf_file(filename, 'r', mmap=True) as f:
time_var = f.variables['time']
# time_var.assignValue(42) should raise a RuntimeError--not seg. fault!
assert_raises(RuntimeError, time_var.assignValue, 42)
def test_appending_issue_gh_8625():
stream = BytesIO()
with make_simple(stream, mode='w') as f:
f.createDimension('x', 2)
f.createVariable('x', float, ('x',))
f.variables['x'][...] = 1
f.flush()
contents = stream.getvalue()
stream = BytesIO(contents)
with netcdf_file(stream, mode='a') as f:
f.variables['x'][...] = 2
def test_write_invalid_dtype():
dtypes = ['int64', 'uint64']
if np.dtype('int').itemsize == 8: # 64-bit machines
dtypes.append('int')
if np.dtype('uint').itemsize == 8: # 64-bit machines
dtypes.append('uint')
with netcdf_file(BytesIO(), 'w') as f:
f.createDimension('time', N_EG_ELS)
for dt in dtypes:
assert_raises(ValueError, f.createVariable, 'time', dt, ('time',))
def test_flush_rewind():
stream = BytesIO()
with make_simple(stream, mode='w') as f:
x = f.createDimension('x',4)
v = f.createVariable('v', 'i2', ['x'])
v[:] = 1
f.flush()
len_single = len(stream.getvalue())
f.flush()
len_double = len(stream.getvalue())
assert_(len_single == len_double)
def test_dtype_specifiers():
# Numpy 1.7.0-dev had a bug where 'i2' wouldn't work.
# Specifying np.int16 or similar only works from the same commit as this
# comment was made.
with make_simple(BytesIO(), mode='w') as f:
f.createDimension('x',4)
f.createVariable('v1', 'i2', ['x'])
f.createVariable('v2', np.int16, ['x'])
f.createVariable('v3', np.dtype(np.int16), ['x'])
def test_ticket_1720():
io = BytesIO()
items = [0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9]
with netcdf_file(io, 'w') as f:
f.history = 'Created for a test'
f.createDimension('float_var', 10)
float_var = f.createVariable('float_var', 'f', ('float_var',))
float_var[:] = items
float_var.units = 'metres'
f.flush()
contents = io.getvalue()
io = BytesIO(contents)
with netcdf_file(io, 'r') as f:
assert_equal(f.history, b'Created for a test')
float_var = f.variables['float_var']
assert_equal(float_var.units, b'metres')
assert_equal(float_var.shape, (10,))
assert_allclose(float_var[:], items)
def test_mmaps_segfault():
filename = pjoin(TEST_DATA_PATH, 'example_1.nc')
if not IS_PYPY:
with warnings.catch_warnings():
warnings.simplefilter("error")
with netcdf_file(filename, mmap=True) as f:
x = f.variables['lat'][:]
# should not raise warnings
del x
def doit():
with netcdf_file(filename, mmap=True) as f:
return f.variables['lat'][:]
# should not crash
with suppress_warnings() as sup:
sup.filter(RuntimeWarning,
"Cannot close a netcdf_file opened with mmap=True, when netcdf_variables or arrays referring to its data still exist")
x = doit()
x.sum()
def test_zero_dimensional_var():
io = BytesIO()
with make_simple(io, 'w') as f:
v = f.createVariable('zerodim', 'i2', [])
# This is checking that .isrec returns a boolean - don't simplify it
# to 'assert not ...'
assert v.isrec is False, v.isrec
f.flush()
def test_byte_gatts():
# Check that global "string" atts work like they did before py3k
# unicode and general bytes confusion
with in_tempdir():
filename = 'g_byte_atts.nc'
f = netcdf_file(filename, 'w')
f._attributes['holy'] = b'grail'
f._attributes['witch'] = 'floats'
f.close()
f = netcdf_file(filename, 'r')
assert_equal(f._attributes['holy'], b'grail')
assert_equal(f._attributes['witch'], b'floats')
f.close()
def test_open_append():
# open 'w' put one attr
with in_tempdir():
filename = 'append_dat.nc'
f = netcdf_file(filename, 'w')
f._attributes['Kilroy'] = 'was here'
f.close()
# open again in 'a', read the att and and a new one
f = netcdf_file(filename, 'a')
assert_equal(f._attributes['Kilroy'], b'was here')
f._attributes['naughty'] = b'Zoot'
f.close()
# open yet again in 'r' and check both atts
f = netcdf_file(filename, 'r')
assert_equal(f._attributes['Kilroy'], b'was here')
assert_equal(f._attributes['naughty'], b'Zoot')
f.close()
def test_append_recordDimension():
dataSize = 100
with in_tempdir():
# Create file with record time dimension
with netcdf_file('withRecordDimension.nc', 'w') as f:
f.createDimension('time', None)
f.createVariable('time', 'd', ('time',))
f.createDimension('x', dataSize)
x = f.createVariable('x', 'd', ('x',))
x[:] = np.array(range(dataSize))
f.createDimension('y', dataSize)
y = f.createVariable('y', 'd', ('y',))
y[:] = np.array(range(dataSize))
f.createVariable('testData', 'i', ('time', 'x', 'y'))
f.flush()
f.close()
for i in range(2):
# Open the file in append mode and add data
with netcdf_file('withRecordDimension.nc', 'a') as f:
f.variables['time'].data = np.append(f.variables["time"].data, i)
f.variables['testData'][i, :, :] = np.ones((dataSize, dataSize))*i
f.flush()
# Read the file and check that append worked
with netcdf_file('withRecordDimension.nc') as f:
assert_equal(f.variables['time'][-1], i)
assert_equal(f.variables['testData'][-1, :, :].copy(), np.ones((dataSize, dataSize))*i)
assert_equal(f.variables['time'].data.shape[0], i+1)
assert_equal(f.variables['testData'].data.shape[0], i+1)
# Read the file and check that 'data' was not saved as user defined
# attribute of testData variable during append operation
with netcdf_file('withRecordDimension.nc') as f:
with assert_raises(KeyError) as ar:
f.variables['testData']._attributes['data']
ex = ar.value
assert_equal(ex.args[0], 'data')
def test_maskandscale():
t = np.linspace(20, 30, 15)
t[3] = 100
tm = np.ma.masked_greater(t, 99)
fname = pjoin(TEST_DATA_PATH, 'example_2.nc')
with netcdf_file(fname, maskandscale=True) as f:
Temp = f.variables['Temperature']
assert_equal(Temp.missing_value, 9999)
assert_equal(Temp.add_offset, 20)
assert_equal(Temp.scale_factor, np.float32(0.01))
found = Temp[:].compressed()
del Temp # Remove ref to mmap, so file can be closed.
expected = np.round(tm.compressed(), 2)
assert_allclose(found, expected)
with in_tempdir():
newfname = 'ms.nc'
f = netcdf_file(newfname, 'w', maskandscale=True)
f.createDimension('Temperature', len(tm))
temp = f.createVariable('Temperature', 'i', ('Temperature',))
temp.missing_value = 9999
temp.scale_factor = 0.01
temp.add_offset = 20
temp[:] = tm
f.close()
with netcdf_file(newfname, maskandscale=True) as f:
Temp = f.variables['Temperature']
assert_equal(Temp.missing_value, 9999)
assert_equal(Temp.add_offset, 20)
assert_equal(Temp.scale_factor, np.float32(0.01))
expected = np.round(tm.compressed(), 2)
found = Temp[:].compressed()
del Temp
assert_allclose(found, expected)
# ------------------------------------------------------------------------
# Test reading with masked values (_FillValue / missing_value)
# ------------------------------------------------------------------------
def test_read_withValuesNearFillValue():
# Regression test for ticket #5626
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var1_fillval0'][:]
assert_mask_matches(vardata, [False, True, False])
def test_read_withNoFillValue():
# For a variable with no fill value, reading data with maskandscale=True
# should return unmasked data
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var2_noFillval'][:]
assert_mask_matches(vardata, [False, False, False])
assert_equal(vardata, [1,2,3])
def test_read_withFillValueAndMissingValue():
# For a variable with both _FillValue and missing_value, the _FillValue
# should be used
IRRELEVANT_VALUE = 9999
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var3_fillvalAndMissingValue'][:]
assert_mask_matches(vardata, [True, False, False])
assert_equal(vardata, [IRRELEVANT_VALUE, 2, 3])
def test_read_withMissingValue():
# For a variable with missing_value but not _FillValue, the missing_value
# should be used
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var4_missingValue'][:]
assert_mask_matches(vardata, [False, True, False])
def test_read_withFillValNaN():
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var5_fillvalNaN'][:]
assert_mask_matches(vardata, [False, True, False])
def test_read_withChar():
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var6_char'][:]
assert_mask_matches(vardata, [False, True, False])
def test_read_with2dVar():
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
with netcdf_file(fname, maskandscale=True) as f:
vardata = f.variables['var7_2d'][:]
assert_mask_matches(vardata, [[True, False], [False, False], [False, True]])
def test_read_withMaskAndScaleFalse():
# If a variable has a _FillValue (or missing_value) attribute, but is read
# with maskandscale set to False, the result should be unmasked
fname = pjoin(TEST_DATA_PATH, 'example_3_maskedvals.nc')
# Open file with mmap=False to avoid problems with closing a mmap'ed file
# when arrays referring to its data still exist:
with netcdf_file(fname, maskandscale=False, mmap=False) as f:
vardata = f.variables['var3_fillvalAndMissingValue'][:]
assert_mask_matches(vardata, [False, False, False])
assert_equal(vardata, [1, 2, 3])