Pillow/Tests/test_file_jpeg.py
2020-06-03 22:11:51 +10:00

728 lines
26 KiB
Python

import os
import re
from io import BytesIO
import pytest
from PIL import ExifTags, Image, ImageFile, JpegImagePlugin
from .helper import (
assert_image,
assert_image_equal,
assert_image_similar,
cjpeg_available,
djpeg_available,
hopper,
is_win32,
skip_unless_feature,
)
TEST_FILE = "Tests/images/hopper.jpg"
@skip_unless_feature("jpg")
class TestFileJpeg:
def roundtrip(self, im, **options):
out = BytesIO()
im.save(out, "JPEG", **options)
test_bytes = out.tell()
out.seek(0)
im = Image.open(out)
im.bytes = test_bytes # for testing only
return im
def gen_random_image(self, size, mode="RGB"):
""" Generates a very hard to compress file
:param size: tuple
:param mode: optional image mode
"""
return Image.frombytes(mode, size, os.urandom(size[0] * size[1] * len(mode)))
def test_sanity(self):
# internal version number
assert re.search(r"\d+\.\d+$", Image.core.jpeglib_version)
with Image.open(TEST_FILE) as im:
im.load()
assert im.mode == "RGB"
assert im.size == (128, 128)
assert im.format == "JPEG"
assert im.get_format_mimetype() == "image/jpeg"
def test_app(self):
# Test APP/COM reader (@PIL135)
with Image.open(TEST_FILE) as im:
assert im.applist[0] == ("APP0", b"JFIF\x00\x01\x01\x01\x00`\x00`\x00\x00")
assert im.applist[1] == (
"COM",
b"File written by Adobe Photoshop\xa8 4.0\x00",
)
assert len(im.applist) == 2
assert im.info["comment"] == b"File written by Adobe Photoshop\xa8 4.0\x00"
def test_cmyk(self):
# Test CMYK handling. Thanks to Tim and Charlie for test data,
# Michael for getting me to look one more time.
f = "Tests/images/pil_sample_cmyk.jpg"
with Image.open(f) as im:
# the source image has red pixels in the upper left corner.
c, m, y, k = [x / 255.0 for x in im.getpixel((0, 0))]
assert c == 0.0
assert m > 0.8
assert y > 0.8
assert k == 0.0
# the opposite corner is black
c, m, y, k = [
x / 255.0 for x in im.getpixel((im.size[0] - 1, im.size[1] - 1))
]
assert k > 0.9
# roundtrip, and check again
im = self.roundtrip(im)
c, m, y, k = [x / 255.0 for x in im.getpixel((0, 0))]
assert c == 0.0
assert m > 0.8
assert y > 0.8
assert k == 0.0
c, m, y, k = [
x / 255.0 for x in im.getpixel((im.size[0] - 1, im.size[1] - 1))
]
assert k > 0.9
def test_dpi(self):
def test(xdpi, ydpi=None):
with Image.open(TEST_FILE) as im:
im = self.roundtrip(im, dpi=(xdpi, ydpi or xdpi))
return im.info.get("dpi")
assert test(72) == (72, 72)
assert test(300) == (300, 300)
assert test(100, 200) == (100, 200)
assert test(0) is None # square pixels
def test_icc(self, tmp_path):
# Test ICC support
with Image.open("Tests/images/rgb.jpg") as im1:
icc_profile = im1.info["icc_profile"]
assert len(icc_profile) == 3144
# Roundtrip via physical file.
f = str(tmp_path / "temp.jpg")
im1.save(f, icc_profile=icc_profile)
with Image.open(f) as im2:
assert im2.info.get("icc_profile") == icc_profile
# Roundtrip via memory buffer.
im1 = self.roundtrip(hopper())
im2 = self.roundtrip(hopper(), icc_profile=icc_profile)
assert_image_equal(im1, im2)
assert not im1.info.get("icc_profile")
assert im2.info.get("icc_profile")
def test_icc_big(self):
# Make sure that the "extra" support handles large blocks
def test(n):
# The ICC APP marker can store 65519 bytes per marker, so
# using a 4-byte test code should allow us to detect out of
# order issues.
icc_profile = (b"Test" * int(n / 4 + 1))[:n]
assert len(icc_profile) == n # sanity
im1 = self.roundtrip(hopper(), icc_profile=icc_profile)
assert im1.info.get("icc_profile") == (icc_profile or None)
test(0)
test(1)
test(3)
test(4)
test(5)
test(65533 - 14) # full JPEG marker block
test(65533 - 14 + 1) # full block plus one byte
test(ImageFile.MAXBLOCK) # full buffer block
test(ImageFile.MAXBLOCK + 1) # full buffer block plus one byte
test(ImageFile.MAXBLOCK * 4 + 3) # large block
def test_large_icc_meta(self, tmp_path):
# https://github.com/python-pillow/Pillow/issues/148
# Sometimes the meta data on the icc_profile block is bigger than
# Image.MAXBLOCK or the image size.
with Image.open("Tests/images/icc_profile_big.jpg") as im:
f = str(tmp_path / "temp.jpg")
icc_profile = im.info["icc_profile"]
# Should not raise OSError for image with icc larger than image size.
im.save(
f,
format="JPEG",
progressive=True,
quality=95,
icc_profile=icc_profile,
optimize=True,
)
def test_optimize(self):
im1 = self.roundtrip(hopper())
im2 = self.roundtrip(hopper(), optimize=0)
im3 = self.roundtrip(hopper(), optimize=1)
assert_image_equal(im1, im2)
assert_image_equal(im1, im3)
assert im1.bytes >= im2.bytes
assert im1.bytes >= im3.bytes
def test_optimize_large_buffer(self, tmp_path):
# https://github.com/python-pillow/Pillow/issues/148
f = str(tmp_path / "temp.jpg")
# this requires ~ 1.5x Image.MAXBLOCK
im = Image.new("RGB", (4096, 4096), 0xFF3333)
im.save(f, format="JPEG", optimize=True)
def test_progressive(self):
im1 = self.roundtrip(hopper())
im2 = self.roundtrip(hopper(), progressive=False)
im3 = self.roundtrip(hopper(), progressive=True)
assert not im1.info.get("progressive")
assert not im2.info.get("progressive")
assert im3.info.get("progressive")
assert_image_equal(im1, im3)
assert im1.bytes >= im3.bytes
def test_progressive_large_buffer(self, tmp_path):
f = str(tmp_path / "temp.jpg")
# this requires ~ 1.5x Image.MAXBLOCK
im = Image.new("RGB", (4096, 4096), 0xFF3333)
im.save(f, format="JPEG", progressive=True)
def test_progressive_large_buffer_highest_quality(self, tmp_path):
f = str(tmp_path / "temp.jpg")
im = self.gen_random_image((255, 255))
# this requires more bytes than pixels in the image
im.save(f, format="JPEG", progressive=True, quality=100)
def test_progressive_cmyk_buffer(self):
# Issue 2272, quality 90 cmyk image is tripping the large buffer bug.
f = BytesIO()
im = self.gen_random_image((256, 256), "CMYK")
im.save(f, format="JPEG", progressive=True, quality=94)
def test_large_exif(self, tmp_path):
# https://github.com/python-pillow/Pillow/issues/148
f = str(tmp_path / "temp.jpg")
im = hopper()
im.save(f, "JPEG", quality=90, exif=b"1" * 65532)
def test_exif_typeerror(self):
with Image.open("Tests/images/exif_typeerror.jpg") as im:
# Should not raise a TypeError
im._getexif()
def test_exif_gps(self):
# Arrange
with Image.open("Tests/images/exif_gps.jpg") as im:
gps_index = 34853
expected_exif_gps = {
0: b"\x00\x00\x00\x01",
2: 4294967295,
5: b"\x01",
30: 65535,
29: "1999:99:99 99:99:99",
}
# Act
exif = im._getexif()
# Assert
assert exif[gps_index] == expected_exif_gps
def test_exif_rollback(self):
# rolling back exif support in 3.1 to pre-3.0 formatting.
# expected from 2.9, with b/u qualifiers switched for 3.2 compatibility
# this test passes on 2.9 and 3.1, but not 3.0
expected_exif = {
34867: 4294967295,
258: (24, 24, 24),
36867: "2099:09:29 10:10:10",
34853: {
0: b"\x00\x00\x00\x01",
2: 4294967295,
5: b"\x01",
30: 65535,
29: "1999:99:99 99:99:99",
},
296: 65535,
34665: 185,
41994: 65535,
514: 4294967295,
271: "Make",
272: "XXX-XXX",
305: "PIL",
42034: (1, 1, 1, 1),
42035: "LensMake",
34856: b"\xaa\xaa\xaa\xaa\xaa\xaa",
282: 4294967295,
33434: 4294967295,
}
with Image.open("Tests/images/exif_gps.jpg") as im:
exif = im._getexif()
for tag, value in expected_exif.items():
assert value == exif[tag]
def test_exif_gps_typeerror(self):
with Image.open("Tests/images/exif_gps_typeerror.jpg") as im:
# Should not raise a TypeError
im._getexif()
def test_progressive_compat(self):
im1 = self.roundtrip(hopper())
assert not im1.info.get("progressive")
assert not im1.info.get("progression")
im2 = self.roundtrip(hopper(), progressive=0)
im3 = self.roundtrip(hopper(), progression=0) # compatibility
assert not im2.info.get("progressive")
assert not im2.info.get("progression")
assert not im3.info.get("progressive")
assert not im3.info.get("progression")
im2 = self.roundtrip(hopper(), progressive=1)
im3 = self.roundtrip(hopper(), progression=1) # compatibility
assert_image_equal(im1, im2)
assert_image_equal(im1, im3)
assert im2.info.get("progressive")
assert im2.info.get("progression")
assert im3.info.get("progressive")
assert im3.info.get("progression")
def test_quality(self):
im1 = self.roundtrip(hopper())
im2 = self.roundtrip(hopper(), quality=50)
assert_image(im1, im2.mode, im2.size)
assert im1.bytes >= im2.bytes
im3 = self.roundtrip(hopper(), quality=0)
assert_image(im1, im3.mode, im3.size)
assert im2.bytes > im3.bytes
def test_smooth(self):
im1 = self.roundtrip(hopper())
im2 = self.roundtrip(hopper(), smooth=100)
assert_image(im1, im2.mode, im2.size)
def test_subsampling(self):
def getsampling(im):
layer = im.layer
return layer[0][1:3] + layer[1][1:3] + layer[2][1:3]
# experimental API
im = self.roundtrip(hopper(), subsampling=-1) # default
assert getsampling(im) == (2, 2, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling=0) # 4:4:4
assert getsampling(im) == (1, 1, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling=1) # 4:2:2
assert getsampling(im) == (2, 1, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling=2) # 4:2:0
assert getsampling(im) == (2, 2, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling=3) # default (undefined)
assert getsampling(im) == (2, 2, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling="4:4:4")
assert getsampling(im) == (1, 1, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling="4:2:2")
assert getsampling(im) == (2, 1, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling="4:2:0")
assert getsampling(im) == (2, 2, 1, 1, 1, 1)
im = self.roundtrip(hopper(), subsampling="4:1:1")
assert getsampling(im) == (2, 2, 1, 1, 1, 1)
with pytest.raises(TypeError):
self.roundtrip(hopper(), subsampling="1:1:1")
def test_exif(self):
with Image.open("Tests/images/pil_sample_rgb.jpg") as im:
info = im._getexif()
assert info[305] == "Adobe Photoshop CS Macintosh"
def test_mp(self):
with Image.open("Tests/images/pil_sample_rgb.jpg") as im:
assert im._getmp() is None
def test_quality_keep(self, tmp_path):
# RGB
with Image.open("Tests/images/hopper.jpg") as im:
f = str(tmp_path / "temp.jpg")
im.save(f, quality="keep")
# Grayscale
with Image.open("Tests/images/hopper_gray.jpg") as im:
f = str(tmp_path / "temp.jpg")
im.save(f, quality="keep")
# CMYK
with Image.open("Tests/images/pil_sample_cmyk.jpg") as im:
f = str(tmp_path / "temp.jpg")
im.save(f, quality="keep")
def test_junk_jpeg_header(self):
# https://github.com/python-pillow/Pillow/issues/630
filename = "Tests/images/junk_jpeg_header.jpg"
with Image.open(filename):
pass
def test_ff00_jpeg_header(self):
filename = "Tests/images/jpeg_ff00_header.jpg"
with Image.open(filename):
pass
def test_truncated_jpeg_should_read_all_the_data(self):
filename = "Tests/images/truncated_jpeg.jpg"
ImageFile.LOAD_TRUNCATED_IMAGES = True
with Image.open(filename) as im:
im.load()
ImageFile.LOAD_TRUNCATED_IMAGES = False
assert im.getbbox() is not None
def test_truncated_jpeg_throws_oserror(self):
filename = "Tests/images/truncated_jpeg.jpg"
with Image.open(filename) as im:
with pytest.raises(OSError):
im.load()
# Test that the error is raised if loaded a second time
with pytest.raises(OSError):
im.load()
def test_qtables(self, tmp_path):
def _n_qtables_helper(n, test_file):
with Image.open(test_file) as im:
f = str(tmp_path / "temp.jpg")
im.save(f, qtables=[[n] * 64] * n)
with Image.open(f) as im:
assert len(im.quantization) == n
reloaded = self.roundtrip(im, qtables="keep")
assert im.quantization == reloaded.quantization
with Image.open("Tests/images/hopper.jpg") as im:
qtables = im.quantization
reloaded = self.roundtrip(im, qtables=qtables, subsampling=0)
assert im.quantization == reloaded.quantization
assert_image_similar(im, self.roundtrip(im, qtables="web_low"), 30)
assert_image_similar(im, self.roundtrip(im, qtables="web_high"), 30)
assert_image_similar(im, self.roundtrip(im, qtables="keep"), 30)
# valid bounds for baseline qtable
bounds_qtable = [int(s) for s in ("255 1 " * 32).split(None)]
self.roundtrip(im, qtables=[bounds_qtable])
# values from wizard.txt in jpeg9-a src package.
standard_l_qtable = [
int(s)
for s in """
16 11 10 16 24 40 51 61
12 12 14 19 26 58 60 55
14 13 16 24 40 57 69 56
14 17 22 29 51 87 80 62
18 22 37 56 68 109 103 77
24 35 55 64 81 104 113 92
49 64 78 87 103 121 120 101
72 92 95 98 112 100 103 99
""".split(
None
)
]
standard_chrominance_qtable = [
int(s)
for s in """
17 18 24 47 99 99 99 99
18 21 26 66 99 99 99 99
24 26 56 99 99 99 99 99
47 66 99 99 99 99 99 99
99 99 99 99 99 99 99 99
99 99 99 99 99 99 99 99
99 99 99 99 99 99 99 99
99 99 99 99 99 99 99 99
""".split(
None
)
]
# list of qtable lists
assert_image_similar(
im,
self.roundtrip(
im, qtables=[standard_l_qtable, standard_chrominance_qtable]
),
30,
)
# tuple of qtable lists
assert_image_similar(
im,
self.roundtrip(
im, qtables=(standard_l_qtable, standard_chrominance_qtable)
),
30,
)
# dict of qtable lists
assert_image_similar(
im,
self.roundtrip(
im, qtables={0: standard_l_qtable, 1: standard_chrominance_qtable}
),
30,
)
_n_qtables_helper(1, "Tests/images/hopper_gray.jpg")
_n_qtables_helper(1, "Tests/images/pil_sample_rgb.jpg")
_n_qtables_helper(2, "Tests/images/pil_sample_rgb.jpg")
_n_qtables_helper(3, "Tests/images/pil_sample_rgb.jpg")
_n_qtables_helper(1, "Tests/images/pil_sample_cmyk.jpg")
_n_qtables_helper(2, "Tests/images/pil_sample_cmyk.jpg")
_n_qtables_helper(3, "Tests/images/pil_sample_cmyk.jpg")
_n_qtables_helper(4, "Tests/images/pil_sample_cmyk.jpg")
# not a sequence
with pytest.raises(ValueError):
self.roundtrip(im, qtables="a")
# sequence wrong length
with pytest.raises(ValueError):
self.roundtrip(im, qtables=[])
# sequence wrong length
with pytest.raises(ValueError):
self.roundtrip(im, qtables=[1, 2, 3, 4, 5])
# qtable entry not a sequence
with pytest.raises(ValueError):
self.roundtrip(im, qtables=[1])
# qtable entry has wrong number of items
with pytest.raises(ValueError):
self.roundtrip(im, qtables=[[1, 2, 3, 4]])
@pytest.mark.skipif(not djpeg_available(), reason="djpeg not available")
def test_load_djpeg(self):
with Image.open(TEST_FILE) as img:
img.load_djpeg()
assert_image_similar(img, Image.open(TEST_FILE), 5)
@pytest.mark.skipif(not cjpeg_available(), reason="cjpeg not available")
def test_save_cjpeg(self, tmp_path):
with Image.open(TEST_FILE) as img:
tempfile = str(tmp_path / "temp.jpg")
JpegImagePlugin._save_cjpeg(img, 0, tempfile)
# Default save quality is 75%, so a tiny bit of difference is alright
assert_image_similar(img, Image.open(tempfile), 17)
def test_no_duplicate_0x1001_tag(self):
# Arrange
tag_ids = {v: k for k, v in ExifTags.TAGS.items()}
# Assert
assert tag_ids["RelatedImageWidth"] == 0x1001
assert tag_ids["RelatedImageLength"] == 0x1002
def test_MAXBLOCK_scaling(self, tmp_path):
im = self.gen_random_image((512, 512))
f = str(tmp_path / "temp.jpeg")
im.save(f, quality=100, optimize=True)
with Image.open(f) as reloaded:
# none of these should crash
reloaded.save(f, quality="keep")
reloaded.save(f, quality="keep", progressive=True)
reloaded.save(f, quality="keep", optimize=True)
def test_bad_mpo_header(self):
""" Treat unknown MPO as JPEG """
# Arrange
# Act
# Shouldn't raise error
fn = "Tests/images/sugarshack_bad_mpo_header.jpg"
with pytest.warns(UserWarning, Image.open, fn) as im:
# Assert
assert im.format == "JPEG"
def test_save_correct_modes(self):
out = BytesIO()
for mode in ["1", "L", "RGB", "RGBX", "CMYK", "YCbCr"]:
img = Image.new(mode, (20, 20))
img.save(out, "JPEG")
def test_save_wrong_modes(self):
# ref https://github.com/python-pillow/Pillow/issues/2005
out = BytesIO()
for mode in ["LA", "La", "RGBA", "RGBa", "P"]:
img = Image.new(mode, (20, 20))
with pytest.raises(OSError):
img.save(out, "JPEG")
def test_save_tiff_with_dpi(self, tmp_path):
# Arrange
outfile = str(tmp_path / "temp.tif")
with Image.open("Tests/images/hopper.tif") as im:
# Act
im.save(outfile, "JPEG", dpi=im.info["dpi"])
# Assert
with Image.open(outfile) as reloaded:
reloaded.load()
assert im.info["dpi"] == reloaded.info["dpi"]
def test_load_dpi_rounding(self):
# Round up
with Image.open("Tests/images/iptc_roundUp.jpg") as im:
assert im.info["dpi"] == (44, 44)
# Round down
with Image.open("Tests/images/iptc_roundDown.jpg") as im:
assert im.info["dpi"] == (2, 2)
def test_save_dpi_rounding(self, tmp_path):
outfile = str(tmp_path / "temp.jpg")
with Image.open("Tests/images/hopper.jpg") as im:
im.save(outfile, dpi=(72.2, 72.2))
with Image.open(outfile) as reloaded:
assert reloaded.info["dpi"] == (72, 72)
im.save(outfile, dpi=(72.8, 72.8))
with Image.open(outfile) as reloaded:
assert reloaded.info["dpi"] == (73, 73)
def test_dpi_tuple_from_exif(self):
# Arrange
# This Photoshop CC 2017 image has DPI in EXIF not metadata
# EXIF XResolution is (2000000, 10000)
with Image.open("Tests/images/photoshop-200dpi.jpg") as im:
# Act / Assert
assert im.info.get("dpi") == (200, 200)
def test_dpi_int_from_exif(self):
# Arrange
# This image has DPI in EXIF not metadata
# EXIF XResolution is 72
with Image.open("Tests/images/exif-72dpi-int.jpg") as im:
# Act / Assert
assert im.info.get("dpi") == (72, 72)
def test_dpi_from_dpcm_exif(self):
# Arrange
# This is photoshop-200dpi.jpg with EXIF resolution unit set to cm:
# exiftool -exif:ResolutionUnit=cm photoshop-200dpi.jpg
with Image.open("Tests/images/exif-200dpcm.jpg") as im:
# Act / Assert
assert im.info.get("dpi") == (508, 508)
def test_dpi_exif_zero_division(self):
# Arrange
# This is photoshop-200dpi.jpg with EXIF resolution set to 0/0:
# exiftool -XResolution=0/0 -YResolution=0/0 photoshop-200dpi.jpg
with Image.open("Tests/images/exif-dpi-zerodivision.jpg") as im:
# Act / Assert
# This should return the default, and not raise a ZeroDivisionError
assert im.info.get("dpi") == (72, 72)
def test_no_dpi_in_exif(self):
# Arrange
# This is photoshop-200dpi.jpg with resolution removed from EXIF:
# exiftool "-*resolution*"= photoshop-200dpi.jpg
with Image.open("Tests/images/no-dpi-in-exif.jpg") as im:
# Act / Assert
# "When the image resolution is unknown, 72 [dpi] is designated."
# http://www.exiv2.org/tags.html
assert im.info.get("dpi") == (72, 72)
def test_invalid_exif(self):
# This is no-dpi-in-exif with the tiff header of the exif block
# hexedited from MM * to FF FF FF FF
with Image.open("Tests/images/invalid-exif.jpg") as im:
# This should return the default, and not a SyntaxError or
# OSError for unidentified image.
assert im.info.get("dpi") == (72, 72)
def test_exif_x_resolution(self, tmp_path):
with Image.open("Tests/images/flower.jpg") as im:
exif = im.getexif()
assert exif[282] == 180
out = str(tmp_path / "out.jpg")
with pytest.warns(None) as record:
im.save(out, exif=exif)
assert len(record) == 0
with Image.open(out) as reloaded:
assert reloaded.getexif()[282] == 180
def test_invalid_exif_x_resolution(self):
# When no x or y resolution is defined in EXIF
with Image.open("Tests/images/invalid-exif-without-x-resolution.jpg") as im:
# This should return the default, and not a ValueError or
# OSError for an unidentified image.
assert im.info.get("dpi") == (72, 72)
def test_ifd_offset_exif(self):
# Arrange
# This image has been manually hexedited to have an IFD offset of 10,
# in contrast to normal 8
with Image.open("Tests/images/exif-ifd-offset.jpg") as im:
# Act / Assert
assert im._getexif()[306] == "2017:03:13 23:03:09"
def test_photoshop(self):
with Image.open("Tests/images/photoshop-200dpi.jpg") as im:
assert im.info["photoshop"][0x03ED] == {
"XResolution": 200.0,
"DisplayedUnitsX": 1,
"YResolution": 200.0,
"DisplayedUnitsY": 1,
}
# Test that the image can still load, even with broken Photoshop data
# This image had the APP13 length hexedited to be smaller
with Image.open("Tests/images/photoshop-200dpi-broken.jpg") as im_broken:
assert_image_equal(im_broken, im)
# This image does not contain a Photoshop header string
with Image.open("Tests/images/app13.jpg") as im:
assert "photoshop" not in im.info
def test_photoshop_malformed_and_multiple(self):
with Image.open("Tests/images/app13-multiple.jpg") as im:
assert "photoshop" in im.info
assert 24 == len(im.info["photoshop"])
apps_13_lengths = [len(v) for k, v in im.applist if k == "APP13"]
assert [65504, 24] == apps_13_lengths
def test_icc_after_SOF(self):
with Image.open("Tests/images/icc-after-SOF.jpg") as im:
assert im.info["icc_profile"] == b"profile"
@pytest.mark.skipif(not is_win32(), reason="Windows only")
@skip_unless_feature("jpg")
class TestFileCloseW32:
def test_fd_leak(self, tmp_path):
tmpfile = str(tmp_path / "temp.jpg")
with Image.open("Tests/images/hopper.jpg") as im:
im.save(tmpfile)
im = Image.open(tmpfile)
fp = im.fp
assert not fp.closed
with pytest.raises(OSError):
os.remove(tmpfile)
im.load()
assert fp.closed
# this should not fail, as load should have closed the file.
os.remove(tmpfile)