Convert P images to RGB before comparing

Tests/helper.py

@@ -55,21 +55,6 @@ def upload(a: Image.Image, b: Image.Image) -> str | None:
     return None
 
 
-def convert_to_comparable(
-    a: Image.Image, b: Image.Image
-) -> tuple[Image.Image, Image.Image]:
-    new_a, new_b = a, b
-    if a.mode == "P":
-        new_a = Image.new("L", a.size)
-        new_b = Image.new("L", b.size)
-        new_a.putdata(a.get_flattened_data())
-        new_b.putdata(b.get_flattened_data())
-    elif a.mode == "I;16":
-        new_a = a.convert("I")
-        new_b = b.convert("I")
-    return new_a, new_b
-
-
 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)}"
@@ -122,8 +107,6 @@ def assert_image_similar(
     assert a.mode == b.mode, msg or f"got mode {repr(a.mode)}, expected {repr(b.mode)}"
     assert a.size == b.size, msg or f"got size {repr(a.size)}, expected {repr(b.size)}"
 
-    a, b = convert_to_comparable(a, b)
-
     diff = 0
     for ach, bch in zip(a.split(), b.split()):
         chdiff = ImageMath.lambda_eval(

Tests/test_file_bmp.py

@@ -215,7 +215,8 @@ def test_rle8() -> None:
 
 def test_rle4() -> None:
     with Image.open("Tests/images/bmp/g/pal4rle.bmp") as im:
-        assert_image_similar_tofile(im, "Tests/images/bmp/g/pal4.bmp", 12)
+        with Image.open("Tests/images/bmp/g/pal4.bmp") as im2:
+            assert_image_equal(im.convert("RGB"), im2.convert("RGB"))
 
 
 def encode_rle4(width: int, palette: bytes, rle: bytes) -> io.BytesIO:

Tests/test_file_gif.py

@@ -375,28 +375,24 @@ def test_palette_handling(tmp_path: Path) -> None:
 
 
 def test_palette_434(tmp_path: Path) -> None:
-    # see https://github.com/python-pillow/Pillow/issues/434
+    # See https://github.com/python-pillow/Pillow/issues/434
 
     def roundtrip(im: Image.Image, **kwargs: bool) -> Image.Image:
         out = tmp_path / "temp.gif"
         im.copy().save(out, "GIF", **kwargs)
-        reloaded = Image.open(out)
+        return Image.open(out)
 
-        return reloaded
+    with Image.open("Tests/images/test.colors.gif") as im:
+        im_rgb = im.convert("RGB")
 
-    orig = "Tests/images/test.colors.gif"
-    with Image.open(orig) as im:
         with roundtrip(im) as reloaded:
-            assert_image_similar(im, reloaded, 1)
+            assert_image_equal(im_rgb, reloaded.convert("RGB"))
         with roundtrip(im, optimize=True) as reloaded:
-            assert_image_similar(im, reloaded, 1)
-
-        im_rgb = im.convert("RGB")
+            assert_image_equal(im_rgb, reloaded.convert("RGB"))
 
     # check automatic P conversion
     with roundtrip(im_rgb) as reloaded:
-        reloaded = reloaded.convert("RGB")
-        assert_image_equal(im_rgb, reloaded)
+        assert_image_equal(im_rgb, reloaded.convert("RGB"))
 
 
 def test_seek() -> None:

Tests/test_file_jpeg2k.py

@@ -19,6 +19,7 @@
 
 from .helper import (
     assert_image_equal,
+    assert_image_equal_tofile,
     assert_image_similar,
     assert_image_similar_tofile,
     skip_unless_feature,
@@ -310,7 +311,7 @@ def test_mct(card: ImageFile.ImageFile) -> None:
 
         assert out.getvalue()[59] == val
         with Image.open(out) as im:
-            assert_image_similar(im, card, 1.0e-3)
+            assert_image_equal(im, card)
 
     # Single component should have MCT disabled
     for val in (0, 1):
@@ -320,7 +321,7 @@ def test_mct(card: ImageFile.ImageFile) -> None:
 
         assert out.getvalue()[53] == 0
         with Image.open(out) as im:
-            assert_image_similar(im, jp2, 1.0e-3)
+            assert_image_equal(im, jp2)
 
 
 def test_sgnd(tmp_path: Path) -> None:
@@ -393,20 +394,11 @@ def test_cmyk_save() -> None:
 
 
 @pytest.mark.parametrize("ext", (".j2k", ".jp2"))
-def test_16bit_monochrome_has_correct_mode(ext: str) -> None:
+def test_16bit_monochrome(ext: str) -> None:
     with Image.open("Tests/images/16bit.cropped" + ext) as im:
-        im.load()
         assert im.mode == "I;16"
 
-
-def test_16bit_monochrome_jp2_like_tiff() -> None:
-    with Image.open("Tests/images/16bit.cropped.tif") as tiff_16bit:
-        assert_image_similar_tofile(tiff_16bit, "Tests/images/16bit.cropped.jp2", 1e-3)
-
-
-def test_16bit_monochrome_j2k_like_tiff() -> None:
-    with Image.open("Tests/images/16bit.cropped.tif") as tiff_16bit:
-        assert_image_similar_tofile(tiff_16bit, "Tests/images/16bit.cropped.j2k", 1e-3)
+        assert_image_equal_tofile(im, "Tests/images/16bit.cropped.tif")
 
 
 def test_16bit_j2k_roundtrips() -> None:

Tests/test_file_xvthumb.py

@@ -16,8 +16,8 @@ def test_open() -> None:
         assert im.format == "XVThumb"
 
         # Create a Hopper image with a similar XV palette
-        im_hopper = hopper().quantize(palette=im)
-        assert_image_similar(im, im_hopper, 9)
+        im_hopper = hopper().quantize(palette=im, dither=Image.Dither.NONE)
+        assert_image_similar(im.convert("RGB"), im_hopper.convert("RGB"), 6.1)
 
 
 def test_unexpected_eof() -> None:

Tests/test_image_reduce.py

@@ -4,7 +4,7 @@
 
 from PIL import Image, ImageMath, ImageMode
 
-from .helper import convert_to_comparable, skip_unless_feature
+from .helper import skip_unless_feature
 
 codecs = dir(Image.core)
 
@@ -202,8 +202,6 @@ def assert_compare_images(
     assert a.mode == b.mode, f"got mode {repr(a.mode)}, expected {repr(b.mode)}"
     assert a.size == b.size, f"got size {repr(a.size)}, expected {repr(b.size)}"
 
-    a, b = convert_to_comparable(a, b)
-
     bands = ImageMode.getmode(a.mode).bands
     for band, ach, bch in zip(bands, a.split(), b.split()):
         ch_diff = ImageMath.lambda_eval(

Tests/test_imagefile.py

@@ -52,7 +52,7 @@ def roundtrip(format: str) -> tuple[Image.Image, Image.Image]:
 
         assert_image_equal(*roundtrip("BMP"))
         im1, im2 = roundtrip("GIF")
-        assert_image_similar(im1.convert("P"), im2, 1)
+        assert_image_equal(im1.convert("RGB"), im2.convert("RGB"))
         with pytest.warns(DeprecationWarning, match="IM image format"):
             assert_image_equal(*roundtrip("IM"))
         assert_image_equal(*roundtrip("MSP"))