Test further scenarios

Tests/test_file_avif.py

@@ -4,7 +4,7 @@
 import os
 import re
 import warnings
-from collections.abc import Generator
+from collections.abc import Generator, Sequence
 from contextlib import contextmanager
 from io import BytesIO
 from pathlib import Path
@@ -289,7 +289,8 @@ def test_exif(self) -> None:
             exif = im.getexif()
         assert exif[274] == 3
 
-    @pytest.mark.parametrize("use_bytes, orientation", [(True, 1), (False, 2)])
+    @pytest.mark.parametrize("use_bytes", [True, False])
+    @pytest.mark.parametrize("orientation", [1, 2])
     def test_exif_save(
         self,
         tmp_path: Path,
@@ -393,7 +394,7 @@ def test_seek(self) -> None:
             with pytest.raises(EOFError):
                 im.seek(1)
 
-    @pytest.mark.parametrize("subsampling", ["4:4:4", "4:2:2", "4:0:0"])
+    @pytest.mark.parametrize("subsampling", ["4:4:4", "4:2:2", "4:2:0", "4:0:0"])
     def test_encoder_subsampling(self, tmp_path: Path, subsampling: str) -> None:
         with Image.open(TEST_AVIF_FILE) as im:
             test_file = str(tmp_path / "temp.avif")
@@ -405,10 +406,11 @@ def test_encoder_subsampling_invalid(self, tmp_path: Path) -> None:
             with pytest.raises(ValueError):
                 im.save(test_file, subsampling="foo")
 
-    def test_encoder_range(self, tmp_path: Path) -> None:
+    @pytest.mark.parametrize("value", ["full", "limited"])
+    def test_encoder_range(self, tmp_path: Path, value: str) -> None:
         with Image.open(TEST_AVIF_FILE) as im:
             test_file = str(tmp_path / "temp.avif")
-            im.save(test_file, range="limited")
+            im.save(test_file, range=value)
 
     def test_encoder_range_invalid(self, tmp_path: Path) -> None:
         with Image.open(TEST_AVIF_FILE) as im:
@@ -444,10 +446,11 @@ def test_decoder_codec_cannot_encode(self, tmp_path: Path) -> None:
                 "enable-chroma-deltaq": "1",
             },
             (("aq-mode", "1"), ("enable-chroma-deltaq", "1")),
+            [("aq-mode", "1"), ("enable-chroma-deltaq", "1")],
         ],
     )
     def test_encoder_advanced_codec_options(
-        self, advanced: dict[str, str] | tuple[tuple[str, str], ...]
+        self, advanced: dict[str, str] | Sequence[tuple[str, str]]
     ) -> None:
         with Image.open(TEST_AVIF_FILE) as im:
             ctrl_buf = BytesIO()
@@ -587,24 +590,25 @@ def test_n_frames(self) -> None:
     def test_write_animation_P(self, tmp_path: Path) -> None:
         """
         Convert an animated GIF to animated AVIF, then compare the frame
-        count, and first and second-to-last frames to ensure they're visually similar.
+        count, and ensure the frames are visually similar to the originals.
         """
 
-        with Image.open("Tests/images/avif/star.gif") as orig:
-            assert orig.n_frames > 1
+        with Image.open("Tests/images/avif/star.gif") as original:
+            assert original.n_frames > 1
 
             temp_file = str(tmp_path / "temp.avif")
-            orig.save(temp_file, save_all=True)
+            original.save(temp_file, save_all=True)
             with Image.open(temp_file) as im:
-                assert im.n_frames == orig.n_frames
+                assert im.n_frames == original.n_frames
 
                 # Compare first frame in P mode to frame from original GIF
-                assert_image_similar(im, orig.convert("RGBA"), 2)
+                assert_image_similar(im, original.convert("RGBA"), 2)
 
-                # Compare second-to-last frame in RGBA mode to frame from original GIF
-                orig.seek(orig.n_frames - 2)
-                im.seek(im.n_frames - 2)
-                assert_image_similar(im, orig, 2.54)
+                # Compare later frames in RGBA mode to frames from original GIF
+                for frame in range(1, original.n_frames):
+                    original.seek(frame)
+                    im.seek(frame)
+                    assert_image_similar(im, original, 2.54)
 
     def test_write_animation_RGBA(self, tmp_path: Path) -> None:
         """