# Copyright (c) 2016, Science and Technology Facilities Council
# This software is distributed under a BSD licence. See LICENSE.txt.
"""
Tests for mrcinterpreter.py
"""
# Import Python 3 features for future-proofing
from __future__ import (absolute_import, division, print_function,
unicode_literals)
import io
import unittest
import warnings
import numpy as np
from .test_mrcobject import MrcObjectTest
from mrcfile.constants import MAP_ID_OFFSET_BYTES
from mrcfile.mrcinterpreter import MrcInterpreter
class MrcInterpreterTest(MrcObjectTest):
"""Unit tests for MrcInterpreter class.
Note that this test class inherits MrcObjectTest to ensure all of the tests
for MrcObject work correctly for the MrcInterpreter subclass.
"""
def setUp(self):
super(MrcInterpreterTest, self).setUp()
# Set up parameters so MrcObject tests run on the MrcInterpreter class
self.mrcobject = MrcInterpreter()
self.mrcobject._create_default_attributes()
def test_incorrect_map_id(self):
stream = io.BytesIO()
stream.write(bytearray(1024))
stream.seek(MAP_ID_OFFSET_BYTES)
stream.write(b'map ')
stream.seek(0)
with self.assertRaisesRegex(ValueError, "Map ID string not found"):
MrcInterpreter(iostream=stream)
def test_incorrect_machine_stamp(self):
stream = io.BytesIO()
stream.write(bytearray(1024))
stream.seek(MAP_ID_OFFSET_BYTES)
stream.write(b'MAP ')
stream.seek(0)
with self.assertRaisesRegex(ValueError, "Unrecognised machine stamp: "
"0x00 0x00 0x00 0x00"):
MrcInterpreter(iostream=stream)
def test_stream_too_short(self):
stream = io.BytesIO()
stream.write(bytearray(1023))
with self.assertRaisesRegex(ValueError, "Couldn't read enough bytes for MRC header"):
MrcInterpreter(iostream=stream)
def test_stream_writing_and_reading(self):
stream = io.BytesIO()
data = np.arange(30, dtype=np.int16).reshape(5, 6)
with MrcInterpreter() as mrc:
mrc._iostream = stream
mrc._create_default_attributes()
mrc.set_data(data)
stream.seek(0)
with MrcInterpreter(iostream=stream) as mrc:
np.testing.assert_array_equal(data, mrc.data)
assert mrc.header.mode == 1
mrc.set_data(data * 2)
assert mrc.header.mode == 1
def test_permissive_read_mode_with_wrong_map_id_and_machine_stamp(self):
stream = io.BytesIO()
stream.write(bytearray(1024))
stream.seek(MAP_ID_OFFSET_BYTES)
stream.write(b'map ')
stream.seek(0)
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter("always")
MrcInterpreter(iostream=stream, permissive=True)
assert len(w) == 2
assert "Map ID string not found" in str(w[0].message)
assert "Unrecognised machine stamp" in str(w[1].message)
def test_permissive_read_mode_with_file_too_small_for_extended_header(self):
stream = io.BytesIO()
mrc = MrcInterpreter()
mrc._iostream = stream
mrc._create_default_attributes()
mrc.set_extended_header(np.arange(12, dtype=np.int16).reshape(1, 3, 4))
mrc.close()
stream.seek(-1, io.SEEK_CUR)
stream.truncate()
stream.seek(0)
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter("always")
MrcInterpreter(iostream=stream, permissive=True)
assert len(w) == 1
assert ("Expected 24 bytes in extended header but could only read 23"
in str(w[0].message))
def test_permissive_read_mode_with_file_too_small_for_data(self):
stream = io.BytesIO()
mrc = MrcInterpreter()
mrc._iostream = stream
mrc._create_default_attributes()
mrc.set_data(np.arange(12, dtype=np.int16).reshape(1, 3, 4))
mrc.close()
stream.seek(-1, io.SEEK_CUR)
stream.truncate()
stream.seek(0)
with warnings.catch_warnings(record=True) as w:
warnings.simplefilter("always")
MrcInterpreter(iostream=stream, permissive=True)
assert len(w) == 1
assert ("Expected 24 bytes in data block but could only read 23"
in str(w[0].message))
if __name__ == '__main__':
unittest.main()
