diff --git a/weasyprint/css/__init__.py b/weasyprint/css/__init__.py
index c49426958..e2df8750b 100644
--- a/weasyprint/css/__init__.py
+++ b/weasyprint/css/__init__.py
@@ -23,14 +23,14 @@
 import cssselect2
 import tinycss2
 
+from .. import CSS
+from ..logger import LOGGER, PROGRESS_LOGGER
+from ..urls import URLFetchingError, get_url_attribute, url_join
 from . import computed_values
 from .properties import INHERITED, INITIAL_NOT_COMPUTED, INITIAL_VALUES
 from .utils import remove_whitespace, split_on_comma
 from .validation import preprocess_declarations
 from .validation.descriptors import preprocess_descriptors
-from .. import CSS
-from ..logger import LOGGER, PROGRESS_LOGGER
-from ..urls import URLFetchingError, get_url_attribute, url_join
 
 # Reject anything not in here:
 PSEUDO_ELEMENTS = (None, 'before', 'after', 'first-line', 'first-letter')
diff --git a/weasyprint/css/computed_values.py b/weasyprint/css/computed_values.py
index 5faf75d4c..6c5476e9b 100644
--- a/weasyprint/css/computed_values.py
+++ b/weasyprint/css/computed_values.py
@@ -14,12 +14,12 @@
 
 from tinycss2.color3 import parse_color
 
-from .properties import INITIAL_VALUES, Dimension
-from .utils import (
-    ANGLE_TO_RADIANS, LENGTH_UNITS, LENGTHS_TO_PIXELS, safe_urljoin)
 from .. import text
 from ..logger import LOGGER
 from ..urls import get_link_attribute
+from .properties import INITIAL_VALUES, Dimension
+from .utils import (
+    ANGLE_TO_RADIANS, LENGTH_UNITS, LENGTHS_TO_PIXELS, safe_urljoin)
 
 ZERO_PIXELS = Dimension(0, 'px')
 
diff --git a/weasyprint/css/utils.py b/weasyprint/css/utils.py
index e652193ff..a8ea5a726 100644
--- a/weasyprint/css/utils.py
+++ b/weasyprint/css/utils.py
@@ -16,10 +16,10 @@
 
 from tinycss2.color3 import parse_color
 
-from .properties import Dimension
 from ..formatting_structure import counters
 from ..images import LinearGradient, RadialGradient
 from ..urls import iri_to_uri, url_is_absolute
+from .properties import Dimension
 
 # http://dev.w3.org/csswg/css3-values/#angles
 # 1<unit> is this many radians.
diff --git a/weasyprint/css/validation/__init__.py b/weasyprint/css/validation/__init__.py
index 618e60fbf..450a02eff 100644
--- a/weasyprint/css/validation/__init__.py
+++ b/weasyprint/css/validation/__init__.py
@@ -12,10 +12,10 @@
 
 from tinycss2 import serialize
 
+from ... import LOGGER
+from ..utils import InvalidValues, remove_whitespace
 from .expanders import EXPANDERS
 from .properties import PREFIX, PROPRIETARY, UNSTABLE, validate_non_shorthand
-from ..utils import InvalidValues, remove_whitespace
-from ... import LOGGER
 
 # Not applicable to the print media
 NOT_PRINT_MEDIA = {
diff --git a/weasyprint/css/validation/descriptors.py b/weasyprint/css/validation/descriptors.py
index ed7728111..765bddea3 100644
--- a/weasyprint/css/validation/descriptors.py
+++ b/weasyprint/css/validation/descriptors.py
@@ -12,11 +12,11 @@
 
 import tinycss2
 
-from . import properties
+from ...logger import LOGGER
 from ..utils import (
     InvalidValues, comma_separated_list, get_keyword, get_single_keyword,
     get_url, remove_whitespace, single_keyword, single_token)
-from ...logger import LOGGER
+from . import properties
 
 DESCRIPTORS = {}
 
diff --git a/weasyprint/css/validation/expanders.py b/weasyprint/css/validation/expanders.py
index c5651dcb7..42ccd70a3 100644
--- a/weasyprint/css/validation/expanders.py
+++ b/weasyprint/css/validation/expanders.py
@@ -13,6 +13,9 @@
 
 from tinycss2.color3 import parse_color
 
+from ..properties import INITIAL_VALUES, Dimension
+from ..utils import (
+    InvalidValues, get_keyword, get_single_keyword, split_on_comma)
 from .descriptors import expand_font_variant
 from .properties import (
     background_attachment, background_image, background_position,
@@ -21,9 +24,6 @@
     flex_wrap, font_family, font_size, font_stretch, font_style, font_weight,
     line_height, list_style_image, list_style_position, list_style_type,
     other_colors, overflow_wrap, validate_non_shorthand)
-from ..properties import INITIAL_VALUES, Dimension
-from ..utils import (
-    InvalidValues, get_keyword, get_single_keyword, split_on_comma)
 
 EXPANDERS = {}
 
diff --git a/weasyprint/css/validation/properties.py b/weasyprint/css/validation/properties.py
index 3179d4bb4..17bce1a7e 100644
--- a/weasyprint/css/validation/properties.py
+++ b/weasyprint/css/validation/properties.py
@@ -12,6 +12,7 @@
 
 from tinycss2.color3 import parse_color
 
+from ...formatting_structure import counters
 from .. import computed_values
 from ..properties import KNOWN_PROPERTIES, Dimension
 from ..utils import (
@@ -19,7 +20,6 @@
     get_content_list_token, get_image, get_keyword, get_length, get_resolution,
     get_single_keyword, get_url, parse_2d_position, parse_background_position,
     parse_function, single_keyword, single_token)
-from ...formatting_structure import counters
 
 PREFIX = '-weasy-'
 PROPRIETARY = set()
diff --git a/weasyprint/formatting_structure/build.py b/weasyprint/formatting_structure/build.py
index cb357a011..0b57d352e 100644
--- a/weasyprint/formatting_structure/build.py
+++ b/weasyprint/formatting_structure/build.py
@@ -19,10 +19,10 @@
 
 import tinycss2.color3
 
-from . import boxes, counters
 from .. import html
 from ..css import properties
 from ..logger import LOGGER
+from . import boxes, counters
 
 # Maps values of the ``display`` CSS property to box types.
 BOX_TYPE_FROM_DISPLAY = {
diff --git a/weasyprint/layout/__init__.py b/weasyprint/layout/__init__.py
index 429ab1c3c..24df36d8d 100644
--- a/weasyprint/layout/__init__.py
+++ b/weasyprint/layout/__init__.py
@@ -20,11 +20,11 @@
 
 from collections import defaultdict
 
+from ..formatting_structure import boxes
+from ..logger import PROGRESS_LOGGER
 from .absolute import absolute_box_layout, absolute_layout
 from .backgrounds import layout_backgrounds
 from .pages import make_all_pages, make_margin_boxes
-from ..formatting_structure import boxes
-from ..logger import PROGRESS_LOGGER
 
 
 def initialize_page_maker(context, root_box):
diff --git a/weasyprint/layout/absolute.py b/weasyprint/layout/absolute.py
index ad7b962f8..0b36d33b2 100644
--- a/weasyprint/layout/absolute.py
+++ b/weasyprint/layout/absolute.py
@@ -7,12 +7,12 @@
 
 """
 
+from ..formatting_structure import boxes
 from .markers import list_marker_layout
 from .min_max import handle_min_max_width
 from .percentages import resolve_percentages, resolve_position_percentages
 from .preferred import shrink_to_fit
 from .tables import table_wrapper_width
-from ..formatting_structure import boxes
 
 
 class AbsolutePlaceholder(object):
diff --git a/weasyprint/layout/backgrounds.py b/weasyprint/layout/backgrounds.py
index 307605edf..556ebfa02 100644
--- a/weasyprint/layout/backgrounds.py
+++ b/weasyprint/layout/backgrounds.py
@@ -10,9 +10,9 @@
 from collections import namedtuple
 from itertools import cycle
 
+from ..formatting_structure import boxes
 from . import replaced
 from .percentages import resolve_radii_percentages
-from ..formatting_structure import boxes
 
 Background = namedtuple('Background', 'color, layers, image_rendering')
 BackgroundLayer = namedtuple(
diff --git a/weasyprint/layout/blocks.py b/weasyprint/layout/blocks.py
index 282b3a37a..899ca821d 100644
--- a/weasyprint/layout/blocks.py
+++ b/weasyprint/layout/blocks.py
@@ -9,6 +9,7 @@
 
 """
 
+from ..formatting_structure import boxes
 from .absolute import AbsolutePlaceholder, absolute_layout
 from .columns import columns_layout
 from .flex import flex_layout
@@ -20,7 +21,6 @@
 from .min_max import handle_min_max_width
 from .percentages import resolve_percentages, resolve_position_percentages
 from .tables import table_layout, table_wrapper_width
-from ..formatting_structure import boxes
 
 
 def block_level_layout(context, box, max_position_y, skip_stack,
diff --git a/weasyprint/layout/columns.py b/weasyprint/layout/columns.py
index 0d63858f2..20db8e0e1 100644
--- a/weasyprint/layout/columns.py
+++ b/weasyprint/layout/columns.py
@@ -11,9 +11,9 @@
 
 from math import floor
 
+from ..formatting_structure import boxes
 from .absolute import absolute_layout
 from .percentages import resolve_percentages
-from ..formatting_structure import boxes
 
 
 def columns_layout(context, box, max_position_y, skip_stack, containing_block,
diff --git a/weasyprint/layout/flex.py b/weasyprint/layout/flex.py
index da33ffc56..36edfef28 100644
--- a/weasyprint/layout/flex.py
+++ b/weasyprint/layout/flex.py
@@ -12,12 +12,12 @@
 import sys
 from math import log10
 
+from ..css.properties import Dimension
+from ..formatting_structure import boxes
 from .markers import list_marker_layout
 from .percentages import resolve_one_percentage, resolve_percentages
 from .preferred import max_content_width, min_content_width
 from .tables import find_in_flow_baseline
-from ..css.properties import Dimension
-from ..formatting_structure import boxes
 
 
 class FlexLine(list):
diff --git a/weasyprint/layout/float.py b/weasyprint/layout/float.py
index f823ae592..949b2260c 100644
--- a/weasyprint/layout/float.py
+++ b/weasyprint/layout/float.py
@@ -9,12 +9,12 @@
 
 """
 
+from ..formatting_structure import boxes
 from .markers import list_marker_layout
 from .min_max import handle_min_max_width
 from .percentages import resolve_percentages, resolve_position_percentages
 from .preferred import shrink_to_fit
 from .tables import table_wrapper_width
-from ..formatting_structure import boxes
 
 
 @handle_min_max_width
diff --git a/weasyprint/layout/inlines.py b/weasyprint/layout/inlines.py
index f827ad502..2a367489a 100644
--- a/weasyprint/layout/inlines.py
+++ b/weasyprint/layout/inlines.py
@@ -11,6 +11,10 @@
 
 import unicodedata
 
+from ..css import computed_from_cascaded
+from ..css.computed_values import ex_ratio, strut_layout
+from ..formatting_structure import boxes
+from ..text import can_break_text, split_first_line
 from .absolute import AbsolutePlaceholder, absolute_layout
 from .flex import flex_layout
 from .float import avoid_collisions, float_layout
@@ -20,10 +24,6 @@
     inline_min_content_width, shrink_to_fit, trailing_whitespace_size)
 from .replaced import image_marker_layout
 from .tables import find_in_flow_baseline, table_wrapper_width
-from ..css import computed_from_cascaded
-from ..css.computed_values import ex_ratio, strut_layout
-from ..formatting_structure import boxes
-from ..text import can_break_text, split_first_line
 
 
 def iter_line_boxes(context, box, position_y, skip_stack, containing_block,
diff --git a/weasyprint/layout/markers.py b/weasyprint/layout/markers.py
index 7a1f62601..8ef62c263 100644
--- a/weasyprint/layout/markers.py
+++ b/weasyprint/layout/markers.py
@@ -9,11 +9,11 @@
 
 """
 
+from ..formatting_structure import boxes
+from ..text import split_first_line
 from .percentages import resolve_percentages
 from .replaced import image_marker_layout
 from .tables import find_in_flow_baseline
-from ..formatting_structure import boxes
-from ..text import split_first_line
 
 
 def list_marker_layout(context, box):
diff --git a/weasyprint/layout/pages.py b/weasyprint/layout/pages.py
index 7f15fcecd..8fdc4b4cc 100644
--- a/weasyprint/layout/pages.py
+++ b/weasyprint/layout/pages.py
@@ -11,15 +11,15 @@
 
 import copy
 
+from ..css import (
+    PageType, computed_from_cascaded, matching_page_types, set_computed_styles)
+from ..formatting_structure import boxes, build
+from ..logger import PROGRESS_LOGGER
 from .absolute import absolute_layout
 from .blocks import block_container_layout, block_level_layout
 from .min_max import handle_min_max_height, handle_min_max_width
 from .percentages import resolve_percentages
 from .preferred import max_content_width, min_content_width
-from ..css import (
-    PageType, computed_from_cascaded, matching_page_types, set_computed_styles)
-from ..formatting_structure import boxes, build
-from ..logger import PROGRESS_LOGGER
 
 
 class OrientedBox(object):
diff --git a/weasyprint/layout/preferred.py b/weasyprint/layout/preferred.py
index 55871fd44..97ec265a9 100644
--- a/weasyprint/layout/preferred.py
+++ b/weasyprint/layout/preferred.py
@@ -15,9 +15,9 @@
 
 import sys
 
-from .replaced import default_image_sizing
 from .. import text
 from ..formatting_structure import boxes
+from .replaced import default_image_sizing
 
 
 def shrink_to_fit(context, box, available_width):
diff --git a/weasyprint/layout/tables.py b/weasyprint/layout/tables.py
index 3be98d6b5..ee8e5d4ee 100644
--- a/weasyprint/layout/tables.py
+++ b/weasyprint/layout/tables.py
@@ -9,10 +9,10 @@
 
 """
 
-from .percentages import resolve_one_percentage, resolve_percentages
-from .preferred import max_content_width, table_and_columns_preferred_widths
 from ..formatting_structure import boxes
 from ..logger import LOGGER
+from .percentages import resolve_one_percentage, resolve_percentages
+from .preferred import max_content_width, table_and_columns_preferred_widths
 
 
 def table_layout(context, table, max_position_y, skip_stack,
diff --git a/weasyprint/tests/test_acid2.py b/weasyprint/tests/test_acid2.py
index 1c42ae83e..a523440a6 100644
--- a/weasyprint/tests/test_acid2.py
+++ b/weasyprint/tests/test_acid2.py
@@ -9,10 +9,10 @@
 
 """
 
+from .. import HTML
 from .test_draw import assert_pixels_equal, image_to_pixels
 from .testing_utils import (
     assert_no_logs, capture_logs, requires, resource_filename)
-from .. import HTML
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_api.py b/weasyprint/tests/test_api.py
index 5fcf64c61..b3869a2e4 100644
--- a/weasyprint/tests/test_api.py
+++ b/weasyprint/tests/test_api.py
@@ -23,11 +23,11 @@
 import py
 import pytest
 
+from .. import CSS, HTML, __main__, default_url_fetcher
+from ..urls import path2url
 from .test_draw import B, _, assert_pixels_equal, image_to_pixels, r
 from .testing_utils import (
     FakeHTML, assert_no_logs, capture_logs, http_server, resource_filename)
-from .. import CSS, HTML, __main__, default_url_fetcher
-from ..urls import path2url
 
 
 def _test_resource(class_, basename, check, **kwargs):
diff --git a/weasyprint/tests/test_boxes.py b/weasyprint/tests/test_boxes.py
index 4a277e42d..e917bff8e 100644
--- a/weasyprint/tests/test_boxes.py
+++ b/weasyprint/tests/test_boxes.py
@@ -13,12 +13,12 @@
 
 import pytest
 
-from .testing_utils import BASE_URL, FakeHTML, assert_no_logs, capture_logs
 from .. import images
 from ..css import PageType, get_all_computed_styles
 from ..css.targets import TargetCollector
 from ..formatting_structure import boxes, build, counters
 from ..layout.pages import set_page_type_computed_styles
+from .testing_utils import BASE_URL, FakeHTML, assert_no_logs, capture_logs
 
 PROPER_CHILDREN = dict((key, tuple(map(tuple, value))) for key, value in {
     # Children can be of *any* type in *one* of the lists.
diff --git a/weasyprint/tests/test_css.py b/weasyprint/tests/test_css.py
index 4ccca0ffb..86b04875e 100644
--- a/weasyprint/tests/test_css.py
+++ b/weasyprint/tests/test_css.py
@@ -12,13 +12,13 @@
 import pytest
 import tinycss2
 
-from .testing_utils import (
-    BASE_URL, FakeHTML, assert_no_logs, capture_logs, resource_filename)
 from .. import CSS, css, default_url_fetcher
 from ..css import PageType, get_all_computed_styles, parse_page_selectors
 from ..css.computed_values import strut_layout
 from ..layout.pages import set_page_type_computed_styles
 from ..urls import path2url
+from .testing_utils import (
+    BASE_URL, FakeHTML, assert_no_logs, capture_logs, resource_filename)
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_css_descriptors.py b/weasyprint/tests/test_css_descriptors.py
index 1ea25410e..569c2cb7e 100644
--- a/weasyprint/tests/test_css_descriptors.py
+++ b/weasyprint/tests/test_css_descriptors.py
@@ -11,9 +11,9 @@
 
 import tinycss2
 
-from .testing_utils import assert_no_logs, capture_logs
 from ..css import preprocess_stylesheet
 from ..css.validation.descriptors import preprocess_descriptors
+from .testing_utils import assert_no_logs, capture_logs
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_css_validation.py b/weasyprint/tests/test_css_validation.py
index ec4b9e554..2bc4b9855 100644
--- a/weasyprint/tests/test_css_validation.py
+++ b/weasyprint/tests/test_css_validation.py
@@ -14,11 +14,11 @@
 import pytest
 import tinycss2
 
-from .testing_utils import assert_no_logs, capture_logs
 from ..css import preprocess_declarations
 from ..css.computed_values import ZERO_PIXELS
 from ..css.properties import INITIAL_VALUES, Dimension
 from ..images import LinearGradient, RadialGradient
+from .testing_utils import assert_no_logs, capture_logs
 
 
 def expand_to_dict(css, expected_error=None):
diff --git a/weasyprint/tests/test_draw/test_background.py b/weasyprint/tests/test_draw/test_background.py
index 3c444e128..984667590 100644
--- a/weasyprint/tests/test_draw/test_background.py
+++ b/weasyprint/tests/test_draw/test_background.py
@@ -11,8 +11,8 @@
 
 import pytest
 
-from . import B, G, _, assert_pixels, r
 from ..testing_utils import assert_no_logs
+from . import B, G, _, assert_pixels, r
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_before_after.py b/weasyprint/tests/test_draw/test_before_after.py
index 9c7893c0b..6e1313425 100644
--- a/weasyprint/tests/test_draw/test_before_after.py
+++ b/weasyprint/tests/test_draw/test_before_after.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import assert_same_rendering
 from ..testing_utils import assert_no_logs
+from . import assert_same_rendering
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_box.py b/weasyprint/tests/test_draw/test_box.py
index f57973810..52cd2d91a 100644
--- a/weasyprint/tests/test_draw/test_box.py
+++ b/weasyprint/tests/test_draw/test_box.py
@@ -11,9 +11,9 @@
 
 import itertools
 
-from . import B, G, R, _, assert_different_renderings, assert_pixels, b, g
-from ..testing_utils import assert_no_logs
 from ... import HTML
+from ..testing_utils import assert_no_logs
+from . import B, G, R, _, assert_different_renderings, assert_pixels, b, g
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_column.py b/weasyprint/tests/test_draw/test_column.py
index ddf6d2df6..7ae9369f6 100644
--- a/weasyprint/tests/test_draw/test_column.py
+++ b/weasyprint/tests/test_draw/test_column.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import _, a, assert_pixels, r
 from ..testing_utils import assert_no_logs, requires
+from . import _, a, assert_pixels, r
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_current_color.py b/weasyprint/tests/test_draw/test_current_color.py
index e83f95044..35dc0e556 100644
--- a/weasyprint/tests/test_draw/test_current_color.py
+++ b/weasyprint/tests/test_draw/test_current_color.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import G, assert_pixels
 from ..testing_utils import assert_no_logs
+from . import G, assert_pixels
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_gradient.py b/weasyprint/tests/test_draw/test_gradient.py
index 4deaa31e3..12bb197f0 100644
--- a/weasyprint/tests/test_draw/test_gradient.py
+++ b/weasyprint/tests/test_draw/test_gradient.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import B, V, _, assert_pixels, html_to_pixels, r, v
 from ..testing_utils import assert_no_logs, requires
+from . import B, V, _, assert_pixels, html_to_pixels, r, v
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_image.py b/weasyprint/tests/test_draw/test_image.py
index 98d1cd2a7..c503c052a 100644
--- a/weasyprint/tests/test_draw/test_image.py
+++ b/weasyprint/tests/test_draw/test_image.py
@@ -11,8 +11,8 @@
 
 import pytest
 
-from . import B, _, a, assert_pixels, assert_same_rendering, r
 from ..testing_utils import assert_no_logs, capture_logs
+from . import B, _, a, assert_pixels, assert_same_rendering, r
 
 centered_image = [
     _ + _ + _ + _ + _ + _ + _ + _,
diff --git a/weasyprint/tests/test_draw/test_list.py b/weasyprint/tests/test_draw/test_list.py
index c4956473e..0bfce7c29 100644
--- a/weasyprint/tests/test_draw/test_list.py
+++ b/weasyprint/tests/test_draw/test_list.py
@@ -11,8 +11,8 @@
 
 import pytest
 
-from . import B, _, assert_pixels, r
 from ..testing_utils import SANS_FONTS, assert_no_logs
+from . import B, _, assert_pixels, r
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_opacity.py b/weasyprint/tests/test_draw/test_opacity.py
index 6772bfb4d..c3eb720d6 100644
--- a/weasyprint/tests/test_draw/test_opacity.py
+++ b/weasyprint/tests/test_draw/test_opacity.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import assert_same_rendering
 from ..testing_utils import assert_no_logs
+from . import assert_same_rendering
 
 opacity_source = '''
     <style>
diff --git a/weasyprint/tests/test_draw/test_overflow.py b/weasyprint/tests/test_draw/test_overflow.py
index 93a2994fc..1f6106230 100644
--- a/weasyprint/tests/test_draw/test_overflow.py
+++ b/weasyprint/tests/test_draw/test_overflow.py
@@ -11,8 +11,8 @@
 
 import pytest
 
-from . import B, _, assert_pixels, g, r
 from ..testing_utils import assert_no_logs, requires
+from . import B, _, assert_pixels, g, r
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_table.py b/weasyprint/tests/test_draw/test_table.py
index 3d7cfff83..cd8ce3192 100644
--- a/weasyprint/tests/test_draw/test_table.py
+++ b/weasyprint/tests/test_draw/test_table.py
@@ -9,9 +9,9 @@
 
 """
 
-from . import B, R, S, _, as_pixel, assert_pixels, p
-from ..testing_utils import assert_no_logs, requires
 from ...html import HTML_HANDLERS
+from ..testing_utils import assert_no_logs, requires
+from . import B, R, S, _, as_pixel, assert_pixels, p
 
 # rgba(255, 0, 0, 0.5) above #fff
 r = as_pixel(b'\xff\x7f\x7f\xff')
diff --git a/weasyprint/tests/test_draw/test_transform.py b/weasyprint/tests/test_draw/test_transform.py
index d89170c0d..1ae1c2fb7 100644
--- a/weasyprint/tests/test_draw/test_transform.py
+++ b/weasyprint/tests/test_draw/test_transform.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import B, _, assert_pixels, r
 from ..testing_utils import assert_no_logs
+from . import B, _, assert_pixels, r
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_draw/test_visibility.py b/weasyprint/tests/test_draw/test_visibility.py
index 9ae2307ba..82c739f41 100644
--- a/weasyprint/tests/test_draw/test_visibility.py
+++ b/weasyprint/tests/test_draw/test_visibility.py
@@ -9,8 +9,8 @@
 
 """
 
-from . import B, _, assert_pixels, r
 from ..testing_utils import assert_no_logs
+from . import B, _, assert_pixels, r
 
 visibility_source = '''
   <style>
diff --git a/weasyprint/tests/test_float.py b/weasyprint/tests/test_float.py
index be43e9953..b20a8f14a 100644
--- a/weasyprint/tests/test_float.py
+++ b/weasyprint/tests/test_float.py
@@ -11,9 +11,9 @@
 
 import pytest
 
+from ..formatting_structure import boxes
 from .test_boxes import render_pages
 from .testing_utils import assert_no_logs
-from ..formatting_structure import boxes
 
 
 def outer_area(box):
diff --git a/weasyprint/tests/test_layout/test_block.py b/weasyprint/tests/test_layout/test_block.py
index 0179b647a..725c53296 100644
--- a/weasyprint/tests/test_layout/test_block.py
+++ b/weasyprint/tests/test_layout/test_block.py
@@ -11,9 +11,9 @@
 
 import pytest
 
+from ...formatting_structure import boxes
 from ..test_boxes import render_pages as parse
 from ..testing_utils import assert_no_logs
-from ...formatting_structure import boxes
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_layout/test_image.py b/weasyprint/tests/test_layout/test_image.py
index 5e5586d28..19d60386f 100644
--- a/weasyprint/tests/test_layout/test_image.py
+++ b/weasyprint/tests/test_layout/test_image.py
@@ -11,9 +11,9 @@
 
 import pytest
 
+from ...formatting_structure import boxes
 from ..test_boxes import render_pages as parse
 from ..testing_utils import assert_no_logs, capture_logs, requires
-from ...formatting_structure import boxes
 
 
 def get_img(html):
diff --git a/weasyprint/tests/test_layout/test_inline.py b/weasyprint/tests/test_layout/test_inline.py
index c856ccf97..f71bfc34b 100644
--- a/weasyprint/tests/test_layout/test_inline.py
+++ b/weasyprint/tests/test_layout/test_inline.py
@@ -11,9 +11,9 @@
 
 import pytest
 
+from ...formatting_structure import boxes
 from ..test_boxes import render_pages as parse
 from ..testing_utils import SANS_FONTS, assert_no_logs
-from ...formatting_structure import boxes
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_layout/test_page.py b/weasyprint/tests/test_layout/test_page.py
index ebf108495..10aaef274 100644
--- a/weasyprint/tests/test_layout/test_page.py
+++ b/weasyprint/tests/test_layout/test_page.py
@@ -11,9 +11,9 @@
 
 import pytest
 
+from ...formatting_structure import boxes
 from ..test_boxes import render_pages
 from ..testing_utils import assert_no_logs
-from ...formatting_structure import boxes
 
 
 @assert_no_logs
diff --git a/weasyprint/tests/test_pdf.py b/weasyprint/tests/test_pdf.py
index 408f4ab16..136b6d4d9 100644
--- a/weasyprint/tests/test_pdf.py
+++ b/weasyprint/tests/test_pdf.py
@@ -17,10 +17,10 @@
 import cairocffi
 import pytest
 
-from .testing_utils import (
-    FakeHTML, assert_no_logs, capture_logs, requires, resource_filename)
 from .. import Attachment, pdf
 from ..urls import path2url
+from .testing_utils import (
+    FakeHTML, assert_no_logs, capture_logs, requires, resource_filename)
 
 # Top of the page is 297mm ~= 842pt
 TOP = 842
diff --git a/weasyprint/tests/test_presentational_hints.py b/weasyprint/tests/test_presentational_hints.py
index 5580eb5fa..294fe2537 100644
--- a/weasyprint/tests/test_presentational_hints.py
+++ b/weasyprint/tests/test_presentational_hints.py
@@ -9,8 +9,8 @@
 
 """
 
-from .testing_utils import BASE_URL, assert_no_logs
 from .. import CSS, HTML
+from .testing_utils import BASE_URL, assert_no_logs
 
 PH_TESTING_CSS = CSS(string='''
 @page {margin: 0; size: 1000px 1000px}
diff --git a/weasyprint/tests/test_stacking.py b/weasyprint/tests/test_stacking.py
index d81447dd3..e2ce537c3 100644
--- a/weasyprint/tests/test_stacking.py
+++ b/weasyprint/tests/test_stacking.py
@@ -9,9 +9,9 @@
 
 import pytest
 
+from ..stacking import StackingContext
 from .test_boxes import render_pages, serialize
 from .testing_utils import assert_no_logs
-from ..stacking import StackingContext
 
 
 def serialize_stacking(context):
diff --git a/weasyprint/tests/test_text.py b/weasyprint/tests/test_text.py
index 28adc32e2..8f9d305d5 100644
--- a/weasyprint/tests/test_text.py
+++ b/weasyprint/tests/test_text.py
@@ -11,10 +11,10 @@
 
 import pytest
 
-from .test_boxes import render_pages
-from .testing_utils import MONO_FONTS, SANS_FONTS, assert_no_logs
 from ..css.properties import INITIAL_VALUES
 from ..text import split_first_line
+from .test_boxes import render_pages
+from .testing_utils import MONO_FONTS, SANS_FONTS, assert_no_logs
 
 
 def make_text(text, width=None, **style):
diff --git a/weasyprint/tests/test_tools.py b/weasyprint/tests/test_tools.py
index 5a11e6b7b..9d522d382 100644
--- a/weasyprint/tests/test_tools.py
+++ b/weasyprint/tests/test_tools.py
@@ -14,9 +14,9 @@
 
 import cairocffi as cairo
 
-from .testing_utils import assert_no_logs
 from ..tools import navigator, renderer
 from ..urls import path2url
+from .testing_utils import assert_no_logs
 
 
 def wsgi_client(module, path_info, qs_args=None, method='GET'):
diff --git a/weasyprint/tests/test_unicode.py b/weasyprint/tests/test_unicode.py
index 90d32f7ad..9a8e3f9dd 100644
--- a/weasyprint/tests/test_unicode.py
+++ b/weasyprint/tests/test_unicode.py
@@ -13,9 +13,9 @@
 import shutil
 import tempfile
 
+from ..urls import ensure_url
 from .test_draw import assert_pixels_equal, document_to_pixels, html_to_pixels
 from .testing_utils import FakeHTML, assert_no_logs, resource_filename
-from ..urls import ensure_url
 
 
 @assert_no_logs