Added type hints

Tests/helper.py

@@ -244,7 +244,7 @@ def fromstring(data: bytes) -> Image.Image:
     return Image.open(BytesIO(data))
 
 
-def tostring(im: Image.Image, string_format: str, **options: dict[str, Any]) -> bytes:
+def tostring(im: Image.Image, string_format: str, **options: Any) -> bytes:
     out = BytesIO()
     im.save(out, string_format, **options)
     return out.getvalue()

Tests/test_image_access.py

@@ -4,6 +4,7 @@ import os
 import subprocess
 import sys
 import sysconfig
+from types import ModuleType
 
 import pytest
 
@@ -23,6 +24,7 @@ else:
     except ImportError:
         cffi = None
 
+numpy: ModuleType | None
 try:
     import numpy
 except ImportError:
@@ -71,9 +73,10 @@ class TestImagePutPixel(AccessTest):
         pix1 = im1.load()
         pix2 = im2.load()
 
-        for x, y in ((0, "0"), ("0", 0)):
+        with pytest.raises(TypeError):
-            with pytest.raises(TypeError):
+            pix1[0, "0"]
-                pix1[x, y]
+        with pytest.raises(TypeError):
+            pix1["0", 0]
 
         for y in range(im1.size[1]):
             for x in range(im1.size[0]):
@@ -123,12 +126,13 @@ class TestImagePutPixel(AccessTest):
         im = hopper()
         pix = im.load()
 
+        assert numpy is not None
         assert pix[numpy.int32(1), numpy.int32(2)] == (18, 20, 59)
 
 
 class TestImageGetPixel(AccessTest):
     @staticmethod
-    def color(mode):
+    def color(mode: str) -> int | tuple[int, ...]:
         bands = Image.getmodebands(mode)
         if bands == 1:
             return 1
@@ -138,12 +142,13 @@ class TestImageGetPixel(AccessTest):
             return (16, 32, 49)
         return tuple(range(1, bands + 1))
 
-    def check(self, mode, expected_color=None) -> None:
+    def check(self, mode: str, expected_color_int: int | None = None) -> None:
         if self._need_cffi_access and mode.startswith("BGR;"):
             pytest.skip("Support not added to deprecated module for BGR;* modes")
 
-        if not expected_color:
+        expected_color = (
-            expected_color = self.color(mode)
+            expected_color_int if expected_color_int is not None else self.color(mode)
+        )
 
         # check putpixel
         im = Image.new(mode, (1, 1), None)
@@ -222,7 +227,7 @@ class TestImageGetPixel(AccessTest):
             "YCbCr",
         ),
     )
-    def test_basic(self, mode) -> None:
+    def test_basic(self, mode: str) -> None:
         self.check(mode)
 
     def test_list(self) -> None:
@@ -231,14 +236,14 @@ class TestImageGetPixel(AccessTest):
 
     @pytest.mark.parametrize("mode", ("I;16", "I;16B"))
     @pytest.mark.parametrize("expected_color", (2**15 - 1, 2**15, 2**15 + 1, 2**16 - 1))
-    def test_signedness(self, mode, expected_color) -> None:
+    def test_signedness(self, mode: str, expected_color: int) -> None:
         # see https://github.com/python-pillow/Pillow/issues/452
         # pixelaccess is using signed int* instead of uint*
         self.check(mode, expected_color)
 
     @pytest.mark.parametrize("mode", ("P", "PA"))
     @pytest.mark.parametrize("color", ((255, 0, 0), (255, 0, 0, 255)))
-    def test_p_putpixel_rgb_rgba(self, mode, color) -> None:
+    def test_p_putpixel_rgb_rgba(self, mode: str, color: tuple[int, ...]) -> None:
         im = Image.new(mode, (1, 1))
         im.putpixel((0, 0), color)
 
@@ -262,7 +267,7 @@ class TestCffiGetPixel(TestImageGetPixel):
 class TestCffi(AccessTest):
     _need_cffi_access = True
 
-    def _test_get_access(self, im) -> None:
+    def _test_get_access(self, im: Image.Image) -> None:
         """Do we get the same thing as the old pixel access
 
         Using private interfaces, forcing a capi access and
@@ -299,7 +304,7 @@ class TestCffi(AccessTest):
         # im = Image.new('I;32B', (10, 10), 2**10)
         # self._test_get_access(im)
 
-    def _test_set_access(self, im, color) -> None:
+    def _test_set_access(self, im: Image.Image, color: tuple[int, ...] | float) -> None:
         """Are we writing the correct bits into the image?
 
         Using private interfaces, forcing a capi access and
@@ -359,7 +364,7 @@ class TestCffi(AccessTest):
                 assert px[i, 0] == 0
 
     @pytest.mark.parametrize("mode", ("P", "PA"))
-    def test_p_putpixel_rgb_rgba(self, mode) -> None:
+    def test_p_putpixel_rgb_rgba(self, mode: str) -> None:
         for color in ((255, 0, 0), (255, 0, 0, 127 if mode == "PA" else 255)):
             im = Image.new(mode, (1, 1))
             with pytest.warns(DeprecationWarning):
@@ -377,7 +382,7 @@ class TestImagePutPixelError(AccessTest):
     INVALID_TYPES = ["foo", 1.0, None]
 
     @pytest.mark.parametrize("mode", IMAGE_MODES1)
-    def test_putpixel_type_error1(self, mode) -> None:
+    def test_putpixel_type_error1(self, mode: str) -> None:
         im = hopper(mode)
         for v in self.INVALID_TYPES:
             with pytest.raises(TypeError, match="color must be int or tuple"):
@@ -400,14 +405,16 @@ class TestImagePutPixelError(AccessTest):
             ),
         ),
     )
-    def test_putpixel_invalid_number_of_bands(self, mode, band_numbers, match) -> None:
+    def test_putpixel_invalid_number_of_bands(
+        self, mode: str, band_numbers: tuple[int, ...], match: str
+    ) -> None:
         im = hopper(mode)
         for band_number in band_numbers:
             with pytest.raises(TypeError, match=match):
                 im.putpixel((0, 0), (0,) * band_number)
 
     @pytest.mark.parametrize("mode", IMAGE_MODES2)
-    def test_putpixel_type_error2(self, mode) -> None:
+    def test_putpixel_type_error2(self, mode: str) -> None:
         im = hopper(mode)
         for v in self.INVALID_TYPES:
             with pytest.raises(
@@ -416,7 +423,7 @@ class TestImagePutPixelError(AccessTest):
                 im.putpixel((0, 0), v)
 
     @pytest.mark.parametrize("mode", IMAGE_MODES1 + IMAGE_MODES2)
-    def test_putpixel_overflow_error(self, mode) -> None:
+    def test_putpixel_overflow_error(self, mode: str) -> None:
         im = hopper(mode)
         with pytest.raises(OverflowError):
             im.putpixel((0, 0), 2**80)
@@ -428,7 +435,7 @@ class TestEmbeddable:
     def test_embeddable(self) -> None:
         import ctypes
 
-        from setuptools.command.build_ext import new_compiler
+        from setuptools.command import build_ext
 
         with open("embed_pil.c", "w", encoding="utf-8") as fh:
             fh.write(
@@ -457,7 +464,7 @@ int main(int argc, char* argv[])
                 % sys.prefix.replace("\\", "\\\\")
             )
 
-        compiler = new_compiler()
+        compiler = getattr(build_ext, "new_compiler")()
         compiler.add_include_dir(sysconfig.get_config_var("INCLUDEPY"))
 
         libdir = sysconfig.get_config_var("LIBDIR") or sysconfig.get_config_var(
@@ -471,7 +478,7 @@ int main(int argc, char* argv[])
         env["PATH"] = sys.prefix + ";" + env["PATH"]
 
         # do not display the Windows Error Reporting dialog
-        ctypes.windll.kernel32.SetErrorMode(0x0002)
+        getattr(ctypes, "windll").kernel32.SetErrorMode(0x0002)
 
         process = subprocess.Popen(["embed_pil.exe"], env=env)
         process.communicate()

Tests/test_image_array.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from typing import Any
+
 import pytest
 from packaging.version import parse as parse_version
 
@@ -13,7 +15,7 @@ im = hopper().resize((128, 100))
 
 
 def test_toarray() -> None:
-    def test(mode):
+    def test(mode: str) -> tuple[tuple[int, ...], str, int]:
         ai = numpy.array(im.convert(mode))
         return ai.shape, ai.dtype.str, ai.nbytes
 
@@ -50,14 +52,14 @@ def test_fromarray() -> None:
     class Wrapper:
         """Class with API matching Image.fromarray"""
 
-        def __init__(self, img, arr_params) -> None:
+        def __init__(self, img: Image.Image, arr_params: dict[str, Any]) -> None:
             self.img = img
             self.__array_interface__ = arr_params
 
-        def tobytes(self):
+        def tobytes(self) -> bytes:
             return self.img.tobytes()
 
-    def test(mode):
+    def test(mode: str) -> tuple[str, tuple[int, int], bool]:
         i = im.convert(mode)
         a = numpy.array(i)
         # Make wrapper instance for image, new array interface

Tests/test_image_draft.py

@@ -7,7 +7,12 @@ from .helper import fromstring, skip_unless_feature, tostring
 pytestmark = skip_unless_feature("jpg")
 
 
-def draft_roundtrip(in_mode, in_size, req_mode, req_size):
+def draft_roundtrip(
+    in_mode: str,
+    in_size: tuple[int, int],
+    req_mode: str | None,
+    req_size: tuple[int, int] | None,
+) -> Image.Image:
     im = Image.new(in_mode, in_size)
     data = tostring(im, "JPEG")
     im = fromstring(data)

Tests/test_image_entropy.py

@@ -4,7 +4,7 @@ from .helper import hopper
 
 
 def test_entropy() -> None:
-    def entropy(mode):
+    def entropy(mode: str) -> float:
         return hopper(mode).entropy()
 
     assert round(abs(entropy("1") - 0.9138803254693582), 7) == 0

Tests/test_image_filter.py

@@ -36,7 +36,7 @@ from .helper import assert_image_equal, hopper
     ),
 )
 @pytest.mark.parametrize("mode", ("L", "I", "RGB", "CMYK"))
-def test_sanity(filter_to_apply, mode) -> None:
+def test_sanity(filter_to_apply: ImageFilter.Filter, mode: str) -> None:
     im = hopper(mode)
     if mode != "I" or isinstance(filter_to_apply, ImageFilter.BuiltinFilter):
         out = im.filter(filter_to_apply)
@@ -45,7 +45,7 @@ def test_sanity(filter_to_apply, mode) -> None:
 
 
 @pytest.mark.parametrize("mode", ("L", "I", "RGB", "CMYK"))
-def test_sanity_error(mode) -> None:
+def test_sanity_error(mode: str) -> None:
     with pytest.raises(TypeError):
         im = hopper(mode)
         im.filter("hello")
@@ -53,7 +53,7 @@ def test_sanity_error(mode) -> None:
 
 # crashes on small images
 @pytest.mark.parametrize("size", ((1, 1), (2, 2), (3, 3)))
-def test_crash(size) -> None:
+def test_crash(size: tuple[int, int]) -> None:
     im = Image.new("RGB", size)
     im.filter(ImageFilter.SMOOTH)
 
@@ -67,7 +67,10 @@ def test_crash(size) -> None:
         ("RGB", ((4, 0, 0), (0, 0, 0))),
     ),
 )
-def test_modefilter(mode, expected) -> None:
+def test_modefilter(
+    mode: str,
+    expected: tuple[int, int] | tuple[tuple[int, int, int], tuple[int, int, int]],
+) -> None:
     im = Image.new(mode, (3, 3), None)
     im.putdata(list(range(9)))
     # image is:
@@ -90,7 +93,13 @@ def test_modefilter(mode, expected) -> None:
         ("F", (0.0, 4.0, 8.0)),
     ),
 )
-def test_rankfilter(mode, expected) -> None:
+def test_rankfilter(
+    mode: str,
+    expected: (
+        tuple[float, float, float]
+        | tuple[tuple[int, int, int], tuple[int, int, int], tuple[int, int, int]]
+    ),
+) -> None:
     im = Image.new(mode, (3, 3), None)
     im.putdata(list(range(9)))
     # image is:
@@ -106,7 +115,7 @@ def test_rankfilter(mode, expected) -> None:
 @pytest.mark.parametrize(
     "filter", (ImageFilter.MinFilter, ImageFilter.MedianFilter, ImageFilter.MaxFilter)
 )
-def test_rankfilter_error(filter) -> None:
+def test_rankfilter_error(filter: ImageFilter.RankFilter) -> None:
     with pytest.raises(ValueError):
         im = Image.new("P", (3, 3), None)
         im.putdata(list(range(9)))
@@ -137,7 +146,7 @@ def test_kernel_not_enough_coefficients() -> None:
 
 
 @pytest.mark.parametrize("mode", ("L", "LA", "I", "RGB", "CMYK"))
-def test_consistency_3x3(mode) -> None:
+def test_consistency_3x3(mode: str) -> None:
     with Image.open("Tests/images/hopper.bmp") as source:
         reference_name = "hopper_emboss"
         reference_name += "_I.png" if mode == "I" else ".bmp"
@@ -163,7 +172,7 @@ def test_consistency_3x3(mode) -> None:
 
 
 @pytest.mark.parametrize("mode", ("L", "LA", "I", "RGB", "CMYK"))
-def test_consistency_5x5(mode) -> None:
+def test_consistency_5x5(mode: str) -> None:
     with Image.open("Tests/images/hopper.bmp") as source:
         reference_name = "hopper_emboss_more"
         reference_name += "_I.png" if mode == "I" else ".bmp"
@@ -199,7 +208,7 @@ def test_consistency_5x5(mode) -> None:
         (2, -2),
     ),
 )
-def test_invalid_box_blur_filter(radius) -> None:
+def test_invalid_box_blur_filter(radius: int | tuple[int, int]) -> None:
     with pytest.raises(ValueError):
         ImageFilter.BoxBlur(radius)
 

Tests/test_image_getextrema.py

@@ -6,7 +6,7 @@ from .helper import hopper
 
 
 def test_extrema() -> None:
-    def extrema(mode):
+    def extrema(mode: str) -> tuple[int, int] | tuple[tuple[int, int], ...]:
         return hopper(mode).getextrema()
 
     assert extrema("1") == (0, 255)

Tests/test_image_getpalette.py

@@ -6,7 +6,7 @@ from .helper import hopper
 
 
 def test_palette() -> None:
-    def palette(mode):
+    def palette(mode: str) -> list[int] | None:
         p = hopper(mode).getpalette()
         if p:
             return p[:10]

Tests/test_image_paste.py

@@ -46,7 +46,7 @@ class TestImagingPaste:
         self.assert_9points_image(im, expected)
 
     @CachedProperty
-    def mask_1(self):
+    def mask_1(self) -> Image.Image:
         mask = Image.new("1", (self.size, self.size))
         px = mask.load()
         for y in range(mask.height):
@@ -55,11 +55,11 @@ class TestImagingPaste:
         return mask
 
     @CachedProperty
-    def mask_L(self):
+    def mask_L(self) -> Image.Image:
         return self.gradient_L.transpose(Image.Transpose.ROTATE_270)
 
     @CachedProperty
-    def gradient_L(self):
+    def gradient_L(self) -> Image.Image:
         gradient = Image.new("L", (self.size, self.size))
         px = gradient.load()
         for y in range(gradient.height):
@@ -68,7 +68,7 @@ class TestImagingPaste:
         return gradient
 
     @CachedProperty
-    def gradient_RGB(self):
+    def gradient_RGB(self) -> Image.Image:
         return Image.merge(
             "RGB",
             [
@@ -79,7 +79,7 @@ class TestImagingPaste:
         )
 
     @CachedProperty
-    def gradient_LA(self):
+    def gradient_LA(self) -> Image.Image:
         return Image.merge(
             "LA",
             [
@@ -89,7 +89,7 @@ class TestImagingPaste:
         )
 
     @CachedProperty
-    def gradient_RGBA(self):
+    def gradient_RGBA(self) -> Image.Image:
         return Image.merge(
             "RGBA",
             [
@@ -101,7 +101,7 @@ class TestImagingPaste:
         )
 
     @CachedProperty
-    def gradient_RGBa(self):
+    def gradient_RGBa(self) -> Image.Image:
         return Image.merge(
             "RGBa",
             [

Tests/test_image_putdata.py

@@ -31,7 +31,7 @@ def test_sanity() -> None:
 
 def test_long_integers() -> None:
     # see bug-200802-systemerror
-    def put(value):
+    def put(value: int) -> tuple[int, int, int, int]:
         im = Image.new("RGBA", (1, 1))
         im.putdata([value])
         return im.getpixel((0, 0))
@@ -58,7 +58,7 @@ def test_mode_with_L_with_float() -> None:
 
 
 @pytest.mark.parametrize("mode", ("I", "I;16", "I;16L", "I;16B"))
-def test_mode_i(mode) -> None:
+def test_mode_i(mode: str) -> None:
     src = hopper("L")
     data = list(src.getdata())
     im = Image.new(mode, src.size, 0)
@@ -79,7 +79,7 @@ def test_mode_F() -> None:
 
 
 @pytest.mark.parametrize("mode", ("BGR;15", "BGR;16", "BGR;24"))
-def test_mode_BGR(mode) -> None:
+def test_mode_BGR(mode: str) -> None:
     data = [(16, 32, 49), (32, 32, 98)]
     im = Image.new(mode, (1, 2))
     im.putdata(data)

Tests/test_image_putpalette.py

@@ -8,7 +8,7 @@ from .helper import assert_image_equal, assert_image_equal_tofile, hopper
 
 
 def test_putpalette() -> None:
-    def palette(mode):
+    def palette(mode: str) -> str | tuple[str, list[int]]:
         im = hopper(mode).copy()
         im.putpalette(list(range(256)) * 3)
         p = im.getpalette()
@@ -81,7 +81,7 @@ def test_putpalette_with_alpha_values() -> None:
         ("RGBAX", (1, 2, 3, 4, 0)),
     ),
 )
-def test_rgba_palette(mode, palette) -> None:
+def test_rgba_palette(mode: str, palette: tuple[int, ...]) -> None:
     im = Image.new("P", (1, 1))
     im.putpalette(palette, mode)
     assert im.getpalette() == [1, 2, 3]

Tests/test_image_resample.py

@@ -231,11 +231,13 @@ class TestImagingCoreResampleAccuracy:
 
 
 class TestCoreResampleConsistency:
-    def make_case(self, mode: str, fill: tuple[int, int, int] | float):
+    def make_case(
+        self, mode: str, fill: tuple[int, int, int] | float
+    ) -> tuple[Image.Image, tuple[int, ...]]:
         im = Image.new(mode, (512, 9), fill)
         return im.resize((9, 512), Image.Resampling.LANCZOS), im.load()[0, 0]
 
-    def run_case(self, case) -> None:
+    def run_case(self, case: tuple[Image.Image, Image.Image]) -> None:
         channel, color = case
         px = channel.load()
         for x in range(channel.size[0]):
@@ -353,7 +355,7 @@ class TestCoreResampleAlphaCorrect:
 
 class TestCoreResamplePasses:
     @contextmanager
-    def count(self, diff):
+    def count(self, diff: int) -> Generator[None, None, None]:
         count = Image.core.get_stats()["new_count"]
         yield
         assert Image.core.get_stats()["new_count"] - count == diff

Tests/test_image_rotate.py

@@ -12,7 +12,13 @@ from .helper import (
 )
 
 
-def rotate(im, mode, angle, center=None, translate=None) -> None:
+def rotate(
+    im: Image.Image,
+    mode: str,
+    angle: int,
+    center: tuple[int, int] | None = None,
+    translate: tuple[int, int] | None = None,
+) -> None:
     out = im.rotate(angle, center=center, translate=translate)
     assert out.mode == mode
     assert out.size == im.size  # default rotate clips output
@@ -27,13 +33,13 @@ def rotate(im, mode, angle, center=None, translate=None) -> None:
 
 
 @pytest.mark.parametrize("mode", ("1", "P", "L", "RGB", "I", "F"))
-def test_mode(mode) -> None:
+def test_mode(mode: str) -> None:
     im = hopper(mode)
     rotate(im, mode, 45)
 
 
 @pytest.mark.parametrize("angle", (0, 90, 180, 270))
-def test_angle(angle) -> None:
+def test_angle(angle: int) -> None:
     with Image.open("Tests/images/test-card.png") as im:
         rotate(im, im.mode, angle)
 
@@ -42,7 +48,7 @@ def test_angle(angle) -> None:
 
 
 @pytest.mark.parametrize("angle", (0, 45, 90, 180, 270))
-def test_zero(angle) -> None:
+def test_zero(angle: int) -> None:
     im = Image.new("RGB", (0, 0))
     rotate(im, im.mode, angle)
 

Tests/test_image_thumbnail.py

@@ -111,7 +111,7 @@ def test_load_first_unless_jpeg() -> None:
     with Image.open("Tests/images/hopper.jpg") as im:
         draft = im.draft
 
-        def im_draft(mode, size):
+        def im_draft(mode: str, size: tuple[int, int]):
             result = draft(mode, size)
             assert result is not None
 

Tests/test_image_transform.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import math
+from typing import Callable
 
 import pytest
 
@@ -91,7 +92,7 @@ class TestImageTransform:
             ("LA", (76, 0)),
         ),
     )
-    def test_fill(self, mode, expected_pixel) -> None:
+    def test_fill(self, mode: str, expected_pixel: tuple[int, ...]) -> None:
         im = hopper(mode)
         (w, h) = im.size
         transformed = im.transform(
@@ -142,7 +143,9 @@ class TestImageTransform:
         assert_image_equal(blank, transformed.crop((w // 2, 0, w, h // 2)))
         assert_image_equal(blank, transformed.crop((0, h // 2, w // 2, h)))
 
-    def _test_alpha_premult(self, op) -> None:
+    def _test_alpha_premult(
+        self, op: Callable[[Image.Image, tuple[int, int]], Image.Image]
+    ) -> None:
         # create image with half white, half black,
         # with the black half transparent.
         # do op,
@@ -159,13 +162,13 @@ class TestImageTransform:
         assert 40 * 10 == hist[-1]
 
     def test_alpha_premult_resize(self) -> None:
-        def op(im, sz):
+        def op(im: Image.Image, sz: tuple[int, int]) -> Image.Image:
             return im.resize(sz, Image.Resampling.BILINEAR)
 
         self._test_alpha_premult(op)
 
     def test_alpha_premult_transform(self) -> None:
-        def op(im, sz):
+        def op(im: Image.Image, sz: tuple[int, int]) -> Image.Image:
             (w, h) = im.size
             return im.transform(
                 sz, Image.Transform.EXTENT, (0, 0, w, h), Image.Resampling.BILINEAR
@@ -173,7 +176,9 @@ class TestImageTransform:
 
         self._test_alpha_premult(op)
 
-    def _test_nearest(self, op, mode) -> None:
+    def _test_nearest(
+        self, op: Callable[[Image.Image, tuple[int, int]], Image.Image], mode: str
+    ) -> None:
         # create white image with half transparent,
         # do op,
         # the image should remain white with half transparent
@@ -196,15 +201,15 @@ class TestImageTransform:
         )
 
     @pytest.mark.parametrize("mode", ("RGBA", "LA"))
-    def test_nearest_resize(self, mode) -> None:
+    def test_nearest_resize(self, mode: str) -> None:
-        def op(im, sz):
+        def op(im: Image.Image, sz: tuple[int, int]) -> Image.Image:
             return im.resize(sz, Image.Resampling.NEAREST)
 
         self._test_nearest(op, mode)
 
     @pytest.mark.parametrize("mode", ("RGBA", "LA"))
-    def test_nearest_transform(self, mode) -> None:
+    def test_nearest_transform(self, mode: str) -> None:
-        def op(im, sz):
+        def op(im: Image.Image, sz: tuple[int, int]) -> Image.Image:
             (w, h) = im.size
             return im.transform(
                 sz, Image.Transform.EXTENT, (0, 0, w, h), Image.Resampling.NEAREST
@@ -227,7 +232,9 @@ class TestImageTransform:
         # Running by default, but I'd totally understand not doing it in
         # the future
 
-        pattern = [Image.new("RGBA", (1024, 1024), (a, a, a, a)) for a in range(1, 65)]
+        pattern: list[Image.Image] | None = [
+            Image.new("RGBA", (1024, 1024), (a, a, a, a)) for a in range(1, 65)
+        ]
 
         # Yeah. Watch some JIT optimize this out.
         pattern = None  # noqa: F841
@@ -240,7 +247,7 @@ class TestImageTransform:
                 im.transform((100, 100), None)
 
     @pytest.mark.parametrize("resample", (Image.Resampling.BOX, "unknown"))
-    def test_unknown_resampling_filter(self, resample) -> None:
+    def test_unknown_resampling_filter(self, resample: Image.Resampling | str) -> None:
         with hopper() as im:
             (w, h) = im.size
             with pytest.raises(ValueError):
@@ -250,7 +257,7 @@ class TestImageTransform:
 class TestImageTransformAffine:
     transform = Image.Transform.AFFINE
 
-    def _test_image(self):
+    def _test_image(self) -> Image.Image:
         im = hopper("RGB")
         return im.crop((10, 20, im.width - 10, im.height - 20))
 
@@ -263,7 +270,7 @@ class TestImageTransformAffine:
             (270, Image.Transpose.ROTATE_270),
         ),
     )
-    def test_rotate(self, deg, transpose) -> None:
+    def test_rotate(self, deg: int, transpose: Image.Transpose | None) -> None:
         im = self._test_image()
 
         angle = -math.radians(deg)
@@ -313,7 +320,13 @@ class TestImageTransformAffine:
             (Image.Resampling.BICUBIC, 1),
         ),
     )
-    def test_resize(self, scale, epsilon_scale, resample, epsilon) -> None:
+    def test_resize(
+        self,
+        scale: float,
+        epsilon_scale: float,
+        resample: Image.Resampling,
+        epsilon: int,
+    ) -> None:
         im = self._test_image()
 
         size_up = int(round(im.width * scale)), int(round(im.height * scale))
@@ -342,7 +355,14 @@ class TestImageTransformAffine:
             (Image.Resampling.BICUBIC, 1),
         ),
     )
-    def test_translate(self, x, y, epsilon_scale, resample, epsilon) -> None:
+    def test_translate(
+        self,
+        x: float,
+        y: float,
+        epsilon_scale: float,
+        resample: Image.Resampling,
+        epsilon: float,
+    ) -> None:
         im = self._test_image()
 
         size_up = int(round(im.width + x)), int(round(im.height + y))