Added type hints to tests (#8203)

Co-authored-by: Andrew Murray <radarhere@users.noreply.github.com>

Tests/helper.py

@@ -60,9 +60,7 @@ def convert_to_comparable(
     return new_a, new_b
 
 
-def assert_deep_equal(
-    a: Sequence[Any], b: Sequence[Any], msg: str | None = None
-) -> None:
+def assert_deep_equal(a: Any, b: Any, msg: str | None = None) -> None:
     try:
         assert len(a) == len(b), msg or f"got length {len(a)}, expected {len(b)}"
     except Exception:

Tests/test_file_libtiff.py

@@ -1048,7 +1048,11 @@ class TestFileLibTiff(LibTiffTestCase):
         ],
     )
     def test_wrong_bits_per_sample(
-        self, file_name: str, mode: str, size: tuple[int, int], tile
+        self,
+        file_name: str,
+        mode: str,
+        size: tuple[int, int],
+        tile: list[tuple[str, tuple[int, int, int, int], int, tuple[Any, ...]]],
     ) -> None:
         with Image.open("Tests/images/" + file_name) as im:
             assert im.mode == mode

Tests/test_file_webp_animated.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from collections.abc import Generator
 from pathlib import Path
 
 import pytest
@@ -96,7 +97,9 @@ def test_write_animation_RGB(tmp_path: Path) -> None:
             check(temp_file1)
 
             # Tests appending using a generator
-            def im_generator(ims):
+            def im_generator(
+                ims: list[Image.Image],
+            ) -> Generator[Image.Image, None, None]:
                 yield from ims
 
             temp_file2 = str(tmp_path / "temp_generator.webp")

Tests/test_image.py

@@ -372,8 +372,9 @@ class TestImage:
         img = Image.alpha_composite(dst, src)
 
         # Assert
-        img_colors = sorted(img.getcolors())
-        assert img_colors == expected_colors
+        img_colors = img.getcolors()
+        assert img_colors is not None
+        assert sorted(img_colors) == expected_colors
 
     def test_alpha_inplace(self) -> None:
         src = Image.new("RGBA", (128, 128), "blue")
@@ -670,7 +671,9 @@ class TestImage:
 
         im_remapped = im.remap_palette([1, 0])
         assert im_remapped.info["transparency"] == 1
-        assert len(im_remapped.getpalette()) == 6
+        palette = im_remapped.getpalette()
+        assert palette is not None
+        assert len(palette) == 6
 
         # Test unused transparency
         im.info["transparency"] = 2

Tests/test_image_access.py

@@ -27,7 +27,9 @@ class TestImagePutPixel:
         for y in range(im1.size[1]):
             for x in range(im1.size[0]):
                 pos = x, y
-                im2.putpixel(pos, im1.getpixel(pos))
+                value = im1.getpixel(pos)
+                assert value is not None
+                im2.putpixel(pos, value)
 
         assert_image_equal(im1, im2)
 
@@ -37,7 +39,9 @@ class TestImagePutPixel:
         for y in range(im1.size[1]):
             for x in range(im1.size[0]):
                 pos = x, y
-                im2.putpixel(pos, im1.getpixel(pos))
+                value = im1.getpixel(pos)
+                assert value is not None
+                im2.putpixel(pos, value)
 
         assert not im2.readonly
         assert_image_equal(im1, im2)
@@ -50,9 +54,9 @@ class TestImagePutPixel:
         assert pix1 is not None
         assert pix2 is not None
         with pytest.raises(TypeError):
-            pix1[0, "0"]
+            pix1[0, "0"]  # type: ignore[index]
         with pytest.raises(TypeError):
-            pix1["0", 0]
+            pix1["0", 0]  # type: ignore[index]
 
         for y in range(im1.size[1]):
             for x in range(im1.size[0]):
@@ -71,7 +75,9 @@ class TestImagePutPixel:
         for y in range(-1, -im1.size[1] - 1, -1):
             for x in range(-1, -im1.size[0] - 1, -1):
                 pos = x, y
-                im2.putpixel(pos, im1.getpixel(pos))
+                value = im1.getpixel(pos)
+                assert value is not None
+                im2.putpixel(pos, value)
 
         assert_image_equal(im1, im2)
 
@@ -81,7 +87,9 @@ class TestImagePutPixel:
         for y in range(-1, -im1.size[1] - 1, -1):
             for x in range(-1, -im1.size[0] - 1, -1):
                 pos = x, y
-                im2.putpixel(pos, im1.getpixel(pos))
+                value = im1.getpixel(pos)
+                assert value is not None
+                im2.putpixel(pos, value)
 
         assert not im2.readonly
         assert_image_equal(im1, im2)
@@ -219,7 +227,7 @@ class TestImagePutPixelError:
         im = hopper(mode)
         for v in self.INVALID_TYPES:
             with pytest.raises(TypeError, match="color must be int or tuple"):
-                im.putpixel((0, 0), v)
+                im.putpixel((0, 0), v)  # type: ignore[arg-type]
 
     @pytest.mark.parametrize(
         ("mode", "band_numbers", "match"),
@@ -253,7 +261,7 @@ class TestImagePutPixelError:
             with pytest.raises(
                 TypeError, match="color must be int or single-element tuple"
             ):
-                im.putpixel((0, 0), v)
+                im.putpixel((0, 0), v)  # type: ignore[arg-type]
 
     @pytest.mark.parametrize("mode", IMAGE_MODES1 + IMAGE_MODES2)
     def test_putpixel_overflow_error(self, mode: str) -> None:

Tests/test_image_convert.py

@@ -225,7 +225,7 @@ def test_l_macro_rounding(convert_mode: str) -> None:
         assert px is not None
         converted_color = px[0, 0]
         if convert_mode == "LA":
-            assert converted_color is not None
+            assert isinstance(converted_color, tuple)
             converted_color = converted_color[0]
         assert converted_color == 1
 

Tests/test_image_getcolors.py

@@ -54,17 +54,21 @@ def test_pack() -> None:
     assert A is None
 
     A = im.getcolors(maxcolors=3)
+    assert A is not None
     A.sort()
     assert A == expected
 
     A = im.getcolors(maxcolors=4)
+    assert A is not None
     A.sort()
     assert A == expected
 
     A = im.getcolors(maxcolors=8)
+    assert A is not None
     A.sort()
     assert A == expected
 
     A = im.getcolors(maxcolors=16)
+    assert A is not None
     A.sort()
     assert A == expected

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: int) -> tuple[int, int, int, int]:
+    def put(value: int) -> float | tuple[int, ...] | None:
         im = Image.new("RGBA", (1, 1))
         im.putdata([value])
         return im.getpixel((0, 0))

Tests/test_image_quantize.py

@@ -31,7 +31,9 @@ def test_libimagequant_quantize() -> None:
     converted = image.quantize(100, Image.Quantize.LIBIMAGEQUANT)
     assert converted.mode == "P"
     assert_image_similar(converted.convert("RGB"), image, 15)
-    assert len(converted.getcolors()) == 100
+    colors = converted.getcolors()
+    assert colors is not None
+    assert len(colors) == 100
 
 
 def test_octree_quantize() -> None:
@@ -39,7 +41,9 @@ def test_octree_quantize() -> None:
     converted = image.quantize(100, Image.Quantize.FASTOCTREE)
     assert converted.mode == "P"
     assert_image_similar(converted.convert("RGB"), image, 20)
-    assert len(converted.getcolors()) == 100
+    colors = converted.getcolors()
+    assert colors is not None
+    assert len(colors) == 100
 
 
 def test_rgba_quantize() -> None:
@@ -158,4 +162,6 @@ def test_small_palette() -> None:
     im = im.quantize(palette=p)
 
     # Assert
-    assert len(im.getcolors()) == 2
+    quantized_colors = im.getcolors()
+    assert quantized_colors is not None
+    assert len(quantized_colors) == 2

Tests/test_image_resample.py

@@ -237,13 +237,13 @@ class TestImagingCoreResampleAccuracy:
 class TestCoreResampleConsistency:
     def make_case(
         self, mode: str, fill: tuple[int, int, int] | float
-    ) -> tuple[Image.Image, tuple[int, ...]]:
+    ) -> tuple[Image.Image, float | tuple[int, ...]]:
         im = Image.new(mode, (512, 9), fill)
         px = im.load()
         assert px is not None
         return im.resize((9, 512), Image.Resampling.LANCZOS), px[0, 0]
 
-    def run_case(self, case: tuple[Image.Image, int | tuple[int, ...]]) -> None:
+    def run_case(self, case: tuple[Image.Image, float | tuple[int, ...]]) -> None:
         channel, color = case
         px = channel.load()
         assert px is not None
@@ -256,6 +256,7 @@ class TestCoreResampleConsistency:
     def test_8u(self) -> None:
         im, color = self.make_case("RGB", (0, 64, 255))
         r, g, b = im.split()
+        assert isinstance(color, tuple)
         self.run_case((r, color[0]))
         self.run_case((g, color[1]))
         self.run_case((b, color[2]))
@@ -290,7 +291,11 @@ class TestCoreResampleAlphaCorrect:
         px = i.load()
         assert px is not None
         for y in range(i.size[1]):
-            used_colors = {px[x, y][0] for x in range(i.size[0])}
+            used_colors = set()
+            for x in range(i.size[0]):
+                value = px[x, y]
+                assert isinstance(value, tuple)
+                used_colors.add(value[0])
             assert 256 == len(used_colors), (
                 "All colors should be present in resized image. "
                 f"Only {len(used_colors)} on line {y}."
@@ -332,12 +337,13 @@ class TestCoreResampleAlphaCorrect:
         assert px is not None
         for y in range(i.size[1]):
             for x in range(i.size[0]):
-                if px[x, y][-1] != 0 and px[x, y][:-1] != clean_pixel:
+                value = px[x, y]
+                assert isinstance(value, tuple)
+                if value[-1] != 0 and value[:-1] != clean_pixel:
                     message = (
-                        f"pixel at ({x}, {y}) is different:\n"
-                        f"{px[x, y]}\n{clean_pixel}"
+                        f"pixel at ({x}, {y}) is different:\n{value}\n{clean_pixel}"
                     )
-                    assert px[x, y][:3] == clean_pixel, message
+                    assert value[:3] == clean_pixel, message
 
     def test_dirty_pixels_rgba(self) -> None:
         case = self.make_dirty_case("RGBA", (255, 255, 0, 128), (0, 0, 255, 0))

Tests/test_image_transform.py

@@ -192,8 +192,9 @@ class TestImageTransform:
 
         im = op(im, (40, 10))
 
-        colors = sorted(im.getcolors())
-        assert colors == sorted(
+        colors = im.getcolors()
+        assert colors is not None
+        assert sorted(colors) == sorted(
             (
                 (20 * 10, opaque),
                 (20 * 10, transparent),

Tests/test_imagechops.py

@@ -391,23 +391,25 @@ def test_overlay() -> None:
 def test_logical() -> None:
     def table(
         op: Callable[[Image.Image, Image.Image], Image.Image], a: int, b: int
-    ) -> tuple[int, int, int, int]:
+    ) -> list[float]:
         out = []
         for x in (a, b):
             imx = Image.new("1", (1, 1), x)
             for y in (a, b):
                 imy = Image.new("1", (1, 1), y)
-                out.append(op(imx, imy).getpixel((0, 0)))
-        return tuple(out)
+                value = op(imx, imy).getpixel((0, 0))
+                assert not isinstance(value, tuple) and value is not None
+                out.append(value)
+        return out
 
-    assert table(ImageChops.logical_and, 0, 1) == (0, 0, 0, 255)
-    assert table(ImageChops.logical_or, 0, 1) == (0, 255, 255, 255)
-    assert table(ImageChops.logical_xor, 0, 1) == (0, 255, 255, 0)
+    assert table(ImageChops.logical_and, 0, 1) == [0, 0, 0, 255]
+    assert table(ImageChops.logical_or, 0, 1) == [0, 255, 255, 255]
+    assert table(ImageChops.logical_xor, 0, 1) == [0, 255, 255, 0]
 
-    assert table(ImageChops.logical_and, 0, 128) == (0, 0, 0, 255)
-    assert table(ImageChops.logical_or, 0, 128) == (0, 255, 255, 255)
-    assert table(ImageChops.logical_xor, 0, 128) == (0, 255, 255, 0)
+    assert table(ImageChops.logical_and, 0, 128) == [0, 0, 0, 255]
+    assert table(ImageChops.logical_or, 0, 128) == [0, 255, 255, 255]
+    assert table(ImageChops.logical_xor, 0, 128) == [0, 255, 255, 0]
 
-    assert table(ImageChops.logical_and, 0, 255) == (0, 0, 0, 255)
-    assert table(ImageChops.logical_or, 0, 255) == (0, 255, 255, 255)
-    assert table(ImageChops.logical_xor, 0, 255) == (0, 255, 255, 0)
+    assert table(ImageChops.logical_and, 0, 255) == [0, 0, 0, 255]
+    assert table(ImageChops.logical_or, 0, 255) == [0, 255, 255, 255]
+    assert table(ImageChops.logical_xor, 0, 255) == [0, 255, 255, 0]

Tests/test_imagecms.py

@@ -691,7 +691,9 @@ def test_rgb_lab(mode: str) -> None:
 
     im = Image.new("LAB", (1, 1), (255, 0, 0))
     converted_im = im.convert(mode)
-    assert converted_im.getpixel((0, 0))[:3] == (0, 255, 255)
+    value = converted_im.getpixel((0, 0))
+    assert isinstance(value, tuple)
+    assert value[:3] == (0, 255, 255)
 
 
 def test_deprecation() -> None:

Tests/test_imagedraw.py

@@ -1,8 +1,8 @@
 from __future__ import annotations
 
-import contextlib
 import os.path
 from collections.abc import Sequence
+from typing import Callable
 
 import pytest
 
@@ -1422,25 +1422,44 @@ def test_default_font_size() -> None:
 
     im = Image.new("RGB", (220, 25))
     draw = ImageDraw.Draw(im)
-    with contextlib.nullcontext() if freetype_support else pytest.raises(ImportError):
+
+    def check(func: Callable[[], None]) -> None:
+        if freetype_support:
+            func()
+        else:
+            with pytest.raises(ImportError):
+                func()
+
+    def draw_text() -> None:
         draw.text((0, 0), text, font_size=16)
         assert_image_equal_tofile(im, "Tests/images/imagedraw_default_font_size.png")
 
-    with contextlib.nullcontext() if freetype_support else pytest.raises(ImportError):
+    check(draw_text)
+
+    def draw_textlength() -> None:
         assert draw.textlength(text, font_size=16) == 216
 
-    with contextlib.nullcontext() if freetype_support else pytest.raises(ImportError):
+    check(draw_textlength)
+
+    def draw_textbbox() -> None:
         assert draw.textbbox((0, 0), text, font_size=16) == (0, 3, 216, 19)
 
+    check(draw_textbbox)
+
     im = Image.new("RGB", (220, 25))
     draw = ImageDraw.Draw(im)
-    with contextlib.nullcontext() if freetype_support else pytest.raises(ImportError):
+
+    def draw_multiline_text() -> None:
         draw.multiline_text((0, 0), text, font_size=16)
         assert_image_equal_tofile(im, "Tests/images/imagedraw_default_font_size.png")
 
-    with contextlib.nullcontext() if freetype_support else pytest.raises(ImportError):
+    check(draw_multiline_text)
+
+    def draw_multiline_textbbox() -> None:
         assert draw.multiline_textbbox((0, 0), text, font_size=16) == (0, 3, 216, 19)
 
+    check(draw_multiline_textbbox)
+
 
 @pytest.mark.parametrize("bbox", BBOX)
 def test_same_color_outline(bbox: Coords) -> None:

Tests/test_imagefile.py

@@ -305,7 +305,7 @@ class TestPyDecoder(CodecsTest):
     def test_decode(self) -> None:
         decoder = ImageFile.PyDecoder(None)
         with pytest.raises(NotImplementedError):
-            decoder.decode(None)
+            decoder.decode(b"")
 
 
 class TestPyEncoder(CodecsTest):

Tests/test_imagemorph.py

@@ -41,11 +41,15 @@ A = string_to_img(
 def img_to_string(im: Image.Image) -> str:
     """Turn a (small) binary image into a string representation"""
     chars = ".1"
-    width, height = im.size
-    return "\n".join(
-        "".join(chars[im.getpixel((c, r)) > 0] for c in range(width))
-        for r in range(height)
-    )
+    result = []
+    for r in range(im.height):
+        line = ""
+        for c in range(im.width):
+            value = im.getpixel((c, r))
+            assert not isinstance(value, tuple) and value is not None
+            line += chars[value > 0]
+        result.append(line)
+    return "\n".join(result)
 
 
 def img_string_normalize(im: str) -> str:

Tests/test_imageops.py

@@ -259,20 +259,26 @@ def test_colorize_2color() -> None:
     left = (0, 1)
     middle = (127, 1)
     right = (255, 1)
+    value = im_test.getpixel(left)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(left),
+        value,
         (255, 0, 0),
         threshold=1,
         msg="black test pixel incorrect",
     )
+    value = im_test.getpixel(middle)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(middle),
+        value,
         (127, 63, 0),
         threshold=1,
         msg="mid test pixel incorrect",
     )
+    value = im_test.getpixel(right)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(right),
+        value,
         (0, 127, 0),
         threshold=1,
         msg="white test pixel incorrect",
@@ -295,20 +301,26 @@ def test_colorize_2color_offset() -> None:
     left = (25, 1)
     middle = (75, 1)
     right = (125, 1)
+    value = im_test.getpixel(left)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(left),
+        value,
         (255, 0, 0),
         threshold=1,
         msg="black test pixel incorrect",
     )
+    value = im_test.getpixel(middle)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(middle),
+        value,
         (127, 63, 0),
         threshold=1,
         msg="mid test pixel incorrect",
     )
+    value = im_test.getpixel(right)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(right),
+        value,
         (0, 127, 0),
         threshold=1,
         msg="white test pixel incorrect",
@@ -339,29 +351,37 @@ def test_colorize_3color_offset() -> None:
     middle = (100, 1)
     right_middle = (150, 1)
     right = (225, 1)
+    value = im_test.getpixel(left)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(left),
+        value,
         (255, 0, 0),
         threshold=1,
         msg="black test pixel incorrect",
     )
+    value = im_test.getpixel(left_middle)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(left_middle),
+        value,
         (127, 0, 127),
         threshold=1,
         msg="low-mid test pixel incorrect",
     )
+    value = im_test.getpixel(middle)
+    assert isinstance(value, tuple)
+    assert_tuple_approx_equal(value, (0, 0, 255), threshold=1, msg="mid incorrect")
+    value = im_test.getpixel(right_middle)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(middle), (0, 0, 255), threshold=1, msg="mid incorrect"
-    )
-    assert_tuple_approx_equal(
-        im_test.getpixel(right_middle),
+        value,
         (0, 63, 127),
         threshold=1,
         msg="high-mid test pixel incorrect",
     )
+    value = im_test.getpixel(right)
+    assert isinstance(value, tuple)
     assert_tuple_approx_equal(
-        im_test.getpixel(right),
+        value,
         (0, 127, 0),
         threshold=1,
         msg="white test pixel incorrect",
@@ -444,6 +464,7 @@ def test_exif_transpose_xml_without_xmp() -> None:
 
         del im.info["xmp"]
         transposed_im = ImageOps.exif_transpose(im)
+        assert transposed_im is not None
         assert 0x0112 not in transposed_im.getexif()
 
 

Tests/test_imagetk.py

@@ -45,10 +45,12 @@ def test_kw() -> None:
 
             # Test "file"
             im = ImageTk._get_image_from_kw(kw)
+            assert im is not None
             assert_image_equal(im, im1)
 
             # Test "data"
             im = ImageTk._get_image_from_kw(kw)
+            assert im is not None
             assert_image_equal(im, im2)
 
     # Test no relevant entry

Tests/test_tiff_ifdrational.py

@@ -11,7 +11,11 @@ from PIL.TiffImagePlugin import IFDRational
 from .helper import hopper, skip_unless_feature
 
 
-def _test_equal(num, denom, target) -> None:
+def _test_equal(
+    num: float | Fraction | IFDRational,
+    denom: int,
+    target: float | Fraction | IFDRational,
+) -> None:
     t = IFDRational(num, denom)
 
     assert target == t