diff --git a/Tests/test_color_lut.py b/Tests/test_color_lut.py
index 2bb1b57d482..c8886a7796d 100644
--- a/Tests/test_color_lut.py
+++ b/Tests/test_color_lut.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from array import array
+from types import ModuleType
 
 import pytest
 
@@ -8,6 +9,7 @@
 
 from .helper import assert_image_equal
 
+numpy: ModuleType | None
 try:
     import numpy
 except ImportError:
@@ -397,6 +399,7 @@ def test_convert_table(self) -> None:
 
     @pytest.mark.skipif(numpy is None, reason="NumPy not installed")
     def test_numpy_sources(self) -> None:
+        assert numpy is not None
         table = numpy.ones((5, 6, 7, 3), dtype=numpy.float16)
         with pytest.raises(ValueError, match="should have either channels"):
             lut = ImageFilter.Color3DLUT((5, 6, 7), table)
@@ -430,6 +433,7 @@ def test_numpy_sources(self) -> None:
 
     @pytest.mark.skipif(numpy is None, reason="NumPy not installed")
     def test_numpy_formats(self) -> None:
+        assert numpy is not None
         g = Image.linear_gradient("L")
         im = Image.merge(
             "RGB",
diff --git a/Tests/test_core_resources.py b/Tests/test_core_resources.py
index 5eabe8f11ba..2c1de8bc3d2 100644
--- a/Tests/test_core_resources.py
+++ b/Tests/test_core_resources.py
@@ -187,6 +187,6 @@ def test_units(self) -> None:
             {"PILLOW_BLOCKS_MAX": "wat"},
         ),
     )
-    def test_warnings(self, var) -> None:
+    def test_warnings(self, var: dict[str, str]) -> None:
         with pytest.warns(UserWarning):
             Image._apply_env_variables(var)
diff --git a/Tests/test_file_dds.py b/Tests/test_file_dds.py
index b78a0dd8109..ebc0e89a1c5 100644
--- a/Tests/test_file_dds.py
+++ b/Tests/test_file_dds.py
@@ -48,7 +48,7 @@
         TEST_FILE_DX10_BC1_TYPELESS,
     ),
 )
-def test_sanity_dxt1_bc1(image_path) -> None:
+def test_sanity_dxt1_bc1(image_path: str) -> None:
     """Check DXT1 and BC1 images can be opened"""
     with Image.open(TEST_FILE_DXT1.replace(".dds", ".png")) as target:
         target = target.convert("RGBA")
@@ -96,7 +96,7 @@ def test_sanity_dxt5() -> None:
         TEST_FILE_BC4U,
     ),
 )
-def test_sanity_ati1_bc4u(image_path) -> None:
+def test_sanity_ati1_bc4u(image_path: str) -> None:
     """Check ATI1 and BC4U images can be opened"""
 
     with Image.open(image_path) as im:
@@ -117,7 +117,7 @@ def test_sanity_ati1_bc4u(image_path) -> None:
         TEST_FILE_DX10_BC4_TYPELESS,
     ),
 )
-def test_dx10_bc4(image_path) -> None:
+def test_dx10_bc4(image_path: str) -> None:
     """Check DX10 BC4 images can be opened"""
 
     with Image.open(image_path) as im:
@@ -138,7 +138,7 @@ def test_dx10_bc4(image_path) -> None:
         TEST_FILE_BC5U,
     ),
 )
-def test_sanity_ati2_bc5u(image_path) -> None:
+def test_sanity_ati2_bc5u(image_path: str) -> None:
     """Check ATI2 and BC5U images can be opened"""
 
     with Image.open(image_path) as im:
@@ -162,7 +162,7 @@ def test_sanity_ati2_bc5u(image_path) -> None:
         (TEST_FILE_BC5S, TEST_FILE_BC5S),
     ),
 )
-def test_dx10_bc5(image_path, expected_path) -> None:
+def test_dx10_bc5(image_path: str, expected_path: str) -> None:
     """Check DX10 BC5 images can be opened"""
 
     with Image.open(image_path) as im:
@@ -176,7 +176,7 @@ def test_dx10_bc5(image_path, expected_path) -> None:
 
 
 @pytest.mark.parametrize("image_path", (TEST_FILE_BC6H, TEST_FILE_BC6HS))
-def test_dx10_bc6h(image_path) -> None:
+def test_dx10_bc6h(image_path: str) -> None:
     """Check DX10 BC6H/BC6HS images can be opened"""
 
     with Image.open(image_path) as im:
@@ -257,7 +257,7 @@ def test_dx10_r8g8b8a8_unorm_srgb() -> None:
         ("RGBA", (800, 600), TEST_FILE_UNCOMPRESSED_RGB_WITH_ALPHA),
     ],
 )
-def test_uncompressed(mode, size, test_file) -> None:
+def test_uncompressed(mode: str, size: tuple[int, int], test_file: str) -> None:
     """Check uncompressed images can be opened"""
 
     with Image.open(test_file) as im:
@@ -359,7 +359,7 @@ def test_unsupported_bitcount() -> None:
         "Tests/images/unimplemented_pfflags.dds",
     ),
 )
-def test_not_implemented(test_file) -> None:
+def test_not_implemented(test_file: str) -> None:
     with pytest.raises(NotImplementedError):
         with Image.open(test_file):
             pass
@@ -381,7 +381,7 @@ def test_save_unsupported_mode(tmp_path: Path) -> None:
         ("RGBA", "Tests/images/pil123rgba.png"),
     ],
 )
-def test_save(mode, test_file, tmp_path: Path) -> None:
+def test_save(mode: str, test_file: str, tmp_path: Path) -> None:
     out = str(tmp_path / "temp.dds")
     with Image.open(test_file) as im:
         assert im.mode == mode
diff --git a/Tests/test_file_fli.py b/Tests/test_file_fli.py
index a673d4af851..fc524721c2b 100644
--- a/Tests/test_file_fli.py
+++ b/Tests/test_file_fli.py
@@ -147,7 +147,7 @@ def test_seek() -> None:
     ],
 )
 @pytest.mark.timeout(timeout=3)
-def test_timeouts(test_file) -> None:
+def test_timeouts(test_file: str) -> None:
     with open(test_file, "rb") as f:
         with Image.open(f) as im:
             with pytest.raises(OSError):
@@ -160,7 +160,7 @@ def test_timeouts(test_file) -> None:
         "Tests/images/crash-5762152299364352.fli",
     ],
 )
-def test_crash(test_file) -> None:
+def test_crash(test_file: str) -> None:
     with open(test_file, "rb") as f:
         with Image.open(f) as im:
             with pytest.raises(OSError):
diff --git a/Tests/test_file_gribstub.py b/Tests/test_file_gribstub.py
index 4945468be40..096a5b88b21 100644
--- a/Tests/test_file_gribstub.py
+++ b/Tests/test_file_gribstub.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from pathlib import Path
+from typing import IO
 
 import pytest
 
@@ -55,15 +56,15 @@ class TestHandler:
         loaded = False
         saved = False
 
-        def open(self, im) -> None:
+        def open(self, im: Image.Image) -> None:
             self.opened = True
 
-        def load(self, im):
+        def load(self, im: Image.Image) -> Image.Image:
             self.loaded = True
             im.fp.close()
             return Image.new("RGB", (1, 1))
 
-        def save(self, im, fp, filename) -> None:
+        def save(self, im: Image.Image, fp: IO[bytes], filename: str) -> None:
             self.saved = True
 
     handler = TestHandler()
diff --git a/Tests/test_file_hdf5stub.py b/Tests/test_file_hdf5stub.py
index ac3d40bf287..f871e2eff16 100644
--- a/Tests/test_file_hdf5stub.py
+++ b/Tests/test_file_hdf5stub.py
@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from pathlib import Path
+from typing import IO
 
 import pytest
 
@@ -56,15 +57,15 @@ class TestHandler:
         loaded = False
         saved = False
 
-        def open(self, im) -> None:
+        def open(self, im: Image.Image) -> None:
             self.opened = True
 
-        def load(self, im):
+        def load(self, im: Image.Image) -> Image.Image:
             self.loaded = True
             im.fp.close()
             return Image.new("RGB", (1, 1))
 
-        def save(self, im, fp, filename) -> None:
+        def save(self, im: Image.Image, fp: IO[bytes], filename: str) -> None:
             self.saved = True
 
     handler = TestHandler()
diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index 6b0662e0be3..65424214838 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -5,6 +5,7 @@
 import warnings
 from io import BytesIO
 from pathlib import Path
+from types import ModuleType
 from typing import Any
 
 import pytest
@@ -33,6 +34,7 @@
     skip_unless_feature,
 )
 
+ElementTree: ModuleType | None
 try:
     from defusedxml import ElementTree
 except ImportError:
@@ -440,25 +442,25 @@ def getsampling(im: Image.Image):
         for subsampling in (-1, 3):  # (default, invalid)
             im = self.roundtrip(hopper(), subsampling=subsampling)
             assert getsampling(im) == (2, 2, 1, 1, 1, 1)
-        for subsampling in (0, "4:4:4"):
-            im = self.roundtrip(hopper(), subsampling=subsampling)
+        for subsampling1 in (0, "4:4:4"):
+            im = self.roundtrip(hopper(), subsampling=subsampling1)
             assert getsampling(im) == (1, 1, 1, 1, 1, 1)
-        for subsampling in (1, "4:2:2"):
-            im = self.roundtrip(hopper(), subsampling=subsampling)
+        for subsampling1 in (1, "4:2:2"):
+            im = self.roundtrip(hopper(), subsampling=subsampling1)
             assert getsampling(im) == (2, 1, 1, 1, 1, 1)
-        for subsampling in (2, "4:2:0", "4:1:1"):
-            im = self.roundtrip(hopper(), subsampling=subsampling)
+        for subsampling1 in (2, "4:2:0", "4:1:1"):
+            im = self.roundtrip(hopper(), subsampling=subsampling1)
             assert getsampling(im) == (2, 2, 1, 1, 1, 1)
 
         # RGB colorspace
-        for subsampling in (-1, 0, "4:4:4"):
+        for subsampling1 in (-1, 0, "4:4:4"):
             # "4:4:4" doesn't really make sense for RGB, but the conversion
             # to an integer happens at a higher level
-            im = self.roundtrip(hopper(), keep_rgb=True, subsampling=subsampling)
+            im = self.roundtrip(hopper(), keep_rgb=True, subsampling=subsampling1)
             assert getsampling(im) == (1, 1, 1, 1, 1, 1)
-        for subsampling in (1, "4:2:2", 2, "4:2:0", 3):
+        for subsampling1 in (1, "4:2:2", 2, "4:2:0", 3):
             with pytest.raises(OSError):
-                self.roundtrip(hopper(), keep_rgb=True, subsampling=subsampling)
+                self.roundtrip(hopper(), keep_rgb=True, subsampling=subsampling1)
 
         with pytest.raises(TypeError):
             self.roundtrip(hopper(), subsampling="1:1:1")
diff --git a/Tests/test_file_palm.py b/Tests/test_file_palm.py
index 55041a4b202..194f39b30b8 100644
--- a/Tests/test_file_palm.py
+++ b/Tests/test_file_palm.py
@@ -11,7 +11,7 @@
 from .helper import assert_image_equal, hopper, magick_command
 
 
-def helper_save_as_palm(tmp_path: Path, mode) -> None:
+def helper_save_as_palm(tmp_path: Path, mode: str) -> None:
     # Arrange
     im = hopper(mode)
     outfile = str(tmp_path / ("temp_" + mode + ".palm"))
@@ -24,7 +24,7 @@ def helper_save_as_palm(tmp_path: Path, mode) -> None:
     assert os.path.getsize(outfile) > 0
 
 
-def open_with_magick(magick, tmp_path: Path, f):
+def open_with_magick(magick: list[str], tmp_path: Path, f: str) -> Image.Image:
     outfile = str(tmp_path / "temp.png")
     rc = subprocess.call(
         magick + [f, outfile], stdout=subprocess.DEVNULL, stderr=subprocess.STDOUT
@@ -33,7 +33,7 @@ def open_with_magick(magick, tmp_path: Path, f):
     return Image.open(outfile)
 
 
-def roundtrip(tmp_path: Path, mode) -> None:
+def roundtrip(tmp_path: Path, mode: str) -> None:
     magick = magick_command()
     if not magick:
         return
@@ -66,6 +66,6 @@ def test_p_mode(tmp_path: Path) -> None:
 
 
 @pytest.mark.parametrize("mode", ("L", "RGB"))
-def test_oserror(tmp_path: Path, mode) -> None:
+def test_oserror(tmp_path: Path, mode: str) -> None:
     with pytest.raises(OSError):
         helper_save_as_palm(tmp_path, mode)
diff --git a/Tests/test_file_tar.py b/Tests/test_file_tar.py
index 44e78e972dc..6217ebedd8a 100644
--- a/Tests/test_file_tar.py
+++ b/Tests/test_file_tar.py
@@ -19,7 +19,7 @@
         ("jpg", "hopper.jpg", "JPEG"),
     ),
 )
-def test_sanity(codec, test_path, format) -> None:
+def test_sanity(codec: str, test_path: str, format: str) -> None:
     if features.check(codec):
         with TarIO.TarIO(TEST_TAR_FILE, test_path) as tar:
             with Image.open(tar) as im:
diff --git a/Tests/test_file_webp_metadata.py b/Tests/test_file_webp_metadata.py
index fea19694109..8759412408c 100644
--- a/Tests/test_file_webp_metadata.py
+++ b/Tests/test_file_webp_metadata.py
@@ -2,6 +2,7 @@
 
 from io import BytesIO
 from pathlib import Path
+from types import ModuleType
 
 import pytest
 
@@ -14,6 +15,7 @@
     skip_unless_feature("webp_mux"),
 ]
 
+ElementTree: ModuleType | None
 try:
     from defusedxml import ElementTree
 except ImportError:
diff --git a/Tests/test_image.py b/Tests/test_image.py
index 67a7d7eca54..75b28c2dc07 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -8,6 +8,7 @@
 import tempfile
 import warnings
 from pathlib import Path
+from typing import IO
 
 import pytest
 
@@ -61,11 +62,11 @@ class TestImage:
             "HSV",
         ),
     )
-    def test_image_modes_success(self, mode) -> None:
+    def test_image_modes_success(self, mode: str) -> None:
         Image.new(mode, (1, 1))
 
     @pytest.mark.parametrize("mode", ("", "bad", "very very long"))
-    def test_image_modes_fail(self, mode) -> None:
+    def test_image_modes_fail(self, mode: str) -> None:
         with pytest.raises(ValueError) as e:
             Image.new(mode, (1, 1))
         assert str(e.value) == "unrecognized image mode"
@@ -100,7 +101,7 @@ def test_sanity(self) -> None:
 
     def test_repr_pretty(self) -> None:
         class Pretty:
-            def text(self, text) -> None:
+            def text(self, text: str) -> None:
                 self.pretty_output = text
 
         im = Image.new("L", (100, 100))
@@ -184,7 +185,9 @@ def test_fp_name(self, tmp_path: Path) -> None:
         temp_file = str(tmp_path / "temp.jpg")
 
         class FP:
-            def write(self, b) -> None:
+            name: str
+
+            def write(self, b: bytes) -> None:
                 pass
 
         fp = FP()
@@ -538,7 +541,7 @@ def test_check_size(self) -> None:
         "PILLOW_VALGRIND_TEST" in os.environ, reason="Valgrind is slower"
     )
     @pytest.mark.parametrize("size", ((0, 100000000), (100000000, 0)))
-    def test_empty_image(self, size) -> None:
+    def test_empty_image(self, size: tuple[int, int]) -> None:
         Image.new("RGB", size)
 
     def test_storage_neg(self) -> None:
@@ -565,7 +568,7 @@ def test_linear_gradient_wrong_mode(self) -> None:
             Image.linear_gradient(wrong_mode)
 
     @pytest.mark.parametrize("mode", ("L", "P", "I", "F"))
-    def test_linear_gradient(self, mode) -> None:
+    def test_linear_gradient(self, mode: str) -> None:
         # Arrange
         target_file = "Tests/images/linear_gradient.png"
 
@@ -590,7 +593,7 @@ def test_radial_gradient_wrong_mode(self) -> None:
             Image.radial_gradient(wrong_mode)
 
     @pytest.mark.parametrize("mode", ("L", "P", "I", "F"))
-    def test_radial_gradient(self, mode) -> None:
+    def test_radial_gradient(self, mode: str) -> None:
         # Arrange
         target_file = "Tests/images/radial_gradient.png"
 
@@ -665,7 +668,11 @@ def test__new(self) -> None:
         blank_p.palette = None
         blank_pa.palette = None
 
-        def _make_new(base_image, image, palette_result=None) -> None:
+        def _make_new(
+            base_image: Image.Image,
+            image: Image.Image,
+            palette_result: ImagePalette.ImagePalette | None = None,
+        ) -> None:
             new_image = base_image._new(image.im)
             assert new_image.mode == image.mode
             assert new_image.size == image.size
@@ -713,7 +720,7 @@ def test_no_new_file_on_error(self, tmp_path: Path) -> None:
     def test_load_on_nonexclusive_multiframe(self) -> None:
         with open("Tests/images/frozenpond.mpo", "rb") as fp:
 
-            def act(fp) -> None:
+            def act(fp: IO[bytes]) -> None:
                 im = Image.open(fp)
                 im.load()
 
@@ -906,12 +913,12 @@ def test_exif_hide_offsets(self) -> None:
                 assert exif.get_ifd(0xA005)
 
     @pytest.mark.parametrize("size", ((1, 0), (0, 1), (0, 0)))
-    def test_zero_tobytes(self, size) -> None:
+    def test_zero_tobytes(self, size: tuple[int, int]) -> None:
         im = Image.new("RGB", size)
         assert im.tobytes() == b""
 
     @pytest.mark.parametrize("size", ((1, 0), (0, 1), (0, 0)))
-    def test_zero_frombytes(self, size) -> None:
+    def test_zero_frombytes(self, size: tuple[int, int]) -> None:
         Image.frombytes("RGB", size, b"")
 
         im = Image.new("RGB", size)
@@ -996,7 +1003,7 @@ def test_constants(self) -> None:
             "01r_00.pcx",
         ],
     )
-    def test_overrun(self, path) -> None:
+    def test_overrun(self, path: str) -> None:
         """For overrun completeness, test as:
         valgrind pytest -qq Tests/test_image.py::TestImage::test_overrun | grep decode.c
         """
@@ -1023,7 +1030,7 @@ def test_exit_fp(self) -> None:
             pass
         assert not hasattr(im, "fp")
 
-    def test_close_graceful(self, caplog) -> None:
+    def test_close_graceful(self, caplog: pytest.LogCaptureFixture) -> None:
         with Image.open("Tests/images/hopper.jpg") as im:
             copy = im.copy()
             with caplog.at_level(logging.DEBUG):
@@ -1034,10 +1041,10 @@ def test_close_graceful(self, caplog) -> None:
 
 
 class MockEncoder:
-    pass
+    args: tuple[str, ...]
 
 
-def mock_encode(*args):
+def mock_encode(*args: str) -> MockEncoder:
     encoder = MockEncoder()
     encoder.args = args
     return encoder
diff --git a/Tests/test_imagefontctl.py b/Tests/test_imagefontctl.py
index 325e7ef216b..24c7b871a68 100644
--- a/Tests/test_imagefontctl.py
+++ b/Tests/test_imagefontctl.py
@@ -208,7 +208,9 @@ def test_language() -> None:
     ),
     ids=("None", "ltr", "rtl2", "rtl", "ttb"),
 )
-def test_getlength(mode, text, direction, expected) -> None:
+def test_getlength(
+    mode: str, text: str, direction: str | None, expected: float
+) -> None:
     ttf = ImageFont.truetype(FONT_PATH, FONT_SIZE)
     im = Image.new(mode, (1, 1), 0)
     d = ImageDraw.Draw(im)
@@ -230,7 +232,7 @@ def test_getlength(mode, text, direction, expected) -> None:
     ("i" + ("\u030C" * 15) + "i", "i" + "\u032C" * 15 + "i", "\u035Cii", "i\u0305i"),
     ids=("caron-above", "caron-below", "double-breve", "overline"),
 )
-def test_getlength_combine(mode, direction, text) -> None:
+def test_getlength_combine(mode: str, direction: str, text: str) -> None:
     if text == "i\u0305i" and direction == "ttb":
         pytest.skip("fails with this font")
 
@@ -250,7 +252,7 @@ def test_getlength_combine(mode, direction, text) -> None:
 
 
 @pytest.mark.parametrize("anchor", ("lt", "mm", "rb", "sm"))
-def test_anchor_ttb(anchor) -> None:
+def test_anchor_ttb(anchor: str) -> None:
     text = "f"
     path = f"Tests/images/test_anchor_ttb_{text}_{anchor}.png"
     f = ImageFont.truetype("Tests/fonts/NotoSans-Regular.ttf", 120)
@@ -306,7 +308,9 @@ def test_anchor_ttb(anchor) -> None:
 @pytest.mark.parametrize(
     "name, text, anchor, dir, epsilon", combine_tests, ids=[r[0] for r in combine_tests]
 )
-def test_combine(name, text, dir, anchor, epsilon) -> None:
+def test_combine(
+    name: str, text: str, dir: str | None, anchor: str | None, epsilon: float
+) -> None:
     path = f"Tests/images/test_combine_{name}.png"
     f = ImageFont.truetype("Tests/fonts/NotoSans-Regular.ttf", 48)
 
@@ -337,7 +341,7 @@ def test_combine(name, text, dir, anchor, epsilon) -> None:
         ("rm", "right"),  # pass with getsize
     ),
 )
-def test_combine_multiline(anchor, align) -> None:
+def test_combine_multiline(anchor: str, align: str) -> None:
     # test that multiline text uses getlength, not getsize or getbbox
 
     path = f"Tests/images/test_combine_multiline_{anchor}_{align}.png"
diff --git a/Tests/test_imagemorph.py b/Tests/test_imagemorph.py
index 0b0c6d2d31a..46b473d7ac8 100644
--- a/Tests/test_imagemorph.py
+++ b/Tests/test_imagemorph.py
@@ -10,7 +10,7 @@
 from .helper import assert_image_equal_tofile, hopper
 
 
-def string_to_img(image_string):
+def string_to_img(image_string: str) -> Image.Image:
     """Turn a string image representation into a binary image"""
     rows = [s for s in image_string.replace(" ", "").split("\n") if len(s)]
     height = len(rows)
@@ -38,7 +38,7 @@ def string_to_img(image_string):
 )
 
 
-def img_to_string(im):
+def img_to_string(im: Image.Image) -> str:
     """Turn a (small) binary image into a string representation"""
     chars = ".1"
     width, height = im.size
@@ -48,11 +48,11 @@ def img_to_string(im):
     )
 
 
-def img_string_normalize(im):
+def img_string_normalize(im: str) -> str:
     return img_to_string(string_to_img(im))
 
 
-def assert_img_equal_img_string(a, b_string) -> None:
+def assert_img_equal_img_string(a: Image.Image, b_string: str) -> None:
     assert img_to_string(a) == img_string_normalize(b_string)
 
 
@@ -63,7 +63,7 @@ def test_str_to_img() -> None:
 @pytest.mark.parametrize(
     "op", ("corner", "dilation4", "dilation8", "erosion4", "erosion8", "edge")
 )
-def test_lut(op) -> None:
+def test_lut(op: str) -> None:
     lb = ImageMorph.LutBuilder(op_name=op)
     assert lb.get_lut() is None
 
diff --git a/Tests/test_imagepalette.py b/Tests/test_imagepalette.py
index 545229500a6..8e2db15aab7 100644
--- a/Tests/test_imagepalette.py
+++ b/Tests/test_imagepalette.py
@@ -67,7 +67,7 @@ def test_getcolor_rgba_color_rgb_palette() -> None:
         (255, ImagePalette.ImagePalette("RGB", list(range(256)) * 3)),
     ],
 )
-def test_getcolor_not_special(index, palette) -> None:
+def test_getcolor_not_special(index: int, palette: ImagePalette.ImagePalette) -> None:
     im = Image.new("P", (1, 1))
 
     # Do not use transparency index as a new color
diff --git a/Tests/test_pickle.py b/Tests/test_pickle.py
index 560cdbd35f7..ed415953f06 100644
--- a/Tests/test_pickle.py
+++ b/Tests/test_pickle.py
@@ -13,7 +13,9 @@
 FONT_PATH = "Tests/fonts/DejaVuSans/DejaVuSans.ttf"
 
 
-def helper_pickle_file(tmp_path: Path, pickle, protocol, test_file, mode) -> None:
+def helper_pickle_file(
+    tmp_path: Path, protocol: int, test_file: str, mode: str | None
+) -> None:
     # Arrange
     with Image.open(test_file) as im:
         filename = str(tmp_path / "temp.pkl")
@@ -30,7 +32,7 @@ def helper_pickle_file(tmp_path: Path, pickle, protocol, test_file, mode) -> Non
         assert im == loaded_im
 
 
-def helper_pickle_string(pickle, protocol, test_file, mode) -> None:
+def helper_pickle_string(protocol: int, test_file: str, mode: str | None) -> None:
     with Image.open(test_file) as im:
         if mode:
             im = im.convert(mode)
@@ -64,10 +66,12 @@ def helper_pickle_string(pickle, protocol, test_file, mode) -> None:
     ],
 )
 @pytest.mark.parametrize("protocol", range(0, pickle.HIGHEST_PROTOCOL + 1))
-def test_pickle_image(tmp_path: Path, test_file, test_mode, protocol) -> None:
+def test_pickle_image(
+    tmp_path: Path, test_file: str, test_mode: str | None, protocol: int
+) -> None:
     # Act / Assert
-    helper_pickle_string(pickle, protocol, test_file, test_mode)
-    helper_pickle_file(tmp_path, pickle, protocol, test_file, test_mode)
+    helper_pickle_string(protocol, test_file, test_mode)
+    helper_pickle_file(tmp_path, protocol, test_file, test_mode)
 
 
 def test_pickle_la_mode_with_palette(tmp_path: Path) -> None:
@@ -99,7 +103,9 @@ def test_pickle_tell() -> None:
     assert unpickled_image.tell() == 0
 
 
-def helper_assert_pickled_font_images(font1, font2) -> None:
+def helper_assert_pickled_font_images(
+    font1: ImageFont.FreeTypeFont, font2: ImageFont.FreeTypeFont
+) -> None:
     # Arrange
     im1 = Image.new(mode="RGBA", size=(300, 100))
     im2 = Image.new(mode="RGBA", size=(300, 100))
@@ -117,7 +123,7 @@ def helper_assert_pickled_font_images(font1, font2) -> None:
 
 @skip_unless_feature("freetype2")
 @pytest.mark.parametrize("protocol", list(range(0, pickle.HIGHEST_PROTOCOL + 1)))
-def test_pickle_font_string(protocol) -> None:
+def test_pickle_font_string(protocol: int) -> None:
     # Arrange
     font = ImageFont.truetype(FONT_PATH, FONT_SIZE)
 
@@ -131,7 +137,7 @@ def test_pickle_font_string(protocol) -> None:
 
 @skip_unless_feature("freetype2")
 @pytest.mark.parametrize("protocol", list(range(0, pickle.HIGHEST_PROTOCOL + 1)))
-def test_pickle_font_file(tmp_path: Path, protocol) -> None:
+def test_pickle_font_file(tmp_path: Path, protocol: int) -> None:
     # Arrange
     font = ImageFont.truetype(FONT_PATH, FONT_SIZE)
     filename = str(tmp_path / "temp.pkl")
diff --git a/Tests/test_psdraw.py b/Tests/test_psdraw.py
index 797539f35ef..64dfb2c95fb 100644
--- a/Tests/test_psdraw.py
+++ b/Tests/test_psdraw.py
@@ -10,7 +10,7 @@
 from PIL import Image, PSDraw
 
 
-def _create_document(ps) -> None:
+def _create_document(ps: PSDraw.PSDraw) -> None:
     title = "hopper"
     box = (1 * 72, 2 * 72, 7 * 72, 10 * 72)  # in points
 
@@ -50,7 +50,7 @@ def test_draw_postscript(tmp_path: Path) -> None:
 
 
 @pytest.mark.parametrize("buffer", (True, False))
-def test_stdout(buffer) -> None:
+def test_stdout(buffer: bool) -> None:
     # Temporarily redirect stdout
     old_stdout = sys.stdout
 
diff --git a/Tests/test_sgi_crash.py b/Tests/test_sgi_crash.py
index 9442801d05c..3ce31cd2d1e 100644
--- a/Tests/test_sgi_crash.py
+++ b/Tests/test_sgi_crash.py
@@ -21,7 +21,7 @@
         "Tests/images/crash-db8bfa78b19721225425530c5946217720d7df4e.sgi",
     ],
 )
-def test_crashes(test_file) -> None:
+def test_crashes(test_file: str) -> None:
     with open(test_file, "rb") as f:
         with Image.open(f) as im:
             with pytest.raises(OSError):
diff --git a/Tests/test_shell_injection.py b/Tests/test_shell_injection.py
index 3db0660eab7..2a072fd44c5 100644
--- a/Tests/test_shell_injection.py
+++ b/Tests/test_shell_injection.py
@@ -2,6 +2,7 @@
 
 import shutil
 from pathlib import Path
+from typing import Callable
 
 import pytest
 
@@ -17,7 +18,12 @@
 
 @pytest.mark.skipif(is_win32(), reason="Requires Unix or macOS")
 class TestShellInjection:
-    def assert_save_filename_check(self, tmp_path: Path, src_img, save_func) -> None:
+    def assert_save_filename_check(
+        self,
+        tmp_path: Path,
+        src_img: Image.Image,
+        save_func: Callable[[Image.Image, int, str], None],
+    ) -> None:
         for filename in test_filenames:
             dest_file = str(tmp_path / filename)
             save_func(src_img, 0, dest_file)
diff --git a/Tests/test_tiff_crashes.py b/Tests/test_tiff_crashes.py
index 64e781cbada..f51e8b3a8bd 100644
--- a/Tests/test_tiff_crashes.py
+++ b/Tests/test_tiff_crashes.py
@@ -42,7 +42,7 @@
 @pytest.mark.filterwarnings("ignore:Possibly corrupt EXIF data")
 @pytest.mark.filterwarnings("ignore:Metadata warning")
 @pytest.mark.filterwarnings("ignore:Truncated File Read")
-def test_tiff_crashes(test_file):
+def test_tiff_crashes(test_file: str) -> None:
     try:
         with Image.open(test_file) as im:
             im.load()
diff --git a/Tests/test_tiff_ifdrational.py b/Tests/test_tiff_ifdrational.py
index 5368545232b..f6adae3e6e7 100644
--- a/Tests/test_tiff_ifdrational.py
+++ b/Tests/test_tiff_ifdrational.py
@@ -53,9 +53,9 @@ def test_nonetype() -> None:
 
 
 def test_ifd_rational_save(tmp_path: Path) -> None:
-    methods = (True, False)
-    if not features.check("libtiff"):
-        methods = (False,)
+    methods = [True]
+    if features.check("libtiff"):
+        methods.append(False)
 
     for libtiff in methods:
         TiffImagePlugin.WRITE_LIBTIFF = libtiff