Parametrized tests

Tests/test_features.py

@@ -70,14 +70,14 @@ def test_libimagequant_version():
     assert re.search(r"\d+\.\d+\.\d+$", features.version("libimagequant"))
 
 
-def test_check_modules():
-    for feature in features.modules:
-        assert features.check_module(feature) in [True, False]
+@pytest.mark.parametrize("feature", features.modules)
+def test_check_modules(feature):
+    assert features.check_module(feature) in [True, False]
 
 
-def test_check_codecs():
-    for feature in features.codecs:
-        assert features.check_codec(feature) in [True, False]
+@pytest.mark.parametrize("feature", features.codecs)
+def test_check_codecs(feature):
+    assert features.check_codec(feature) in [True, False]
 
 
 def test_check_warns_on_nonexistent():

Tests/test_file_apng.py

@@ -39,13 +39,12 @@ def test_apng_basic():
         assert im.getpixel((64, 32)) == (0, 255, 0, 255)
 
 
-def test_apng_fdat():
-    with Image.open("Tests/images/apng/split_fdat.png") as im:
-        im.seek(im.n_frames - 1)
-        assert im.getpixel((0, 0)) == (0, 255, 0, 255)
-        assert im.getpixel((64, 32)) == (0, 255, 0, 255)
-
-    with Image.open("Tests/images/apng/split_fdat_zero_chunk.png") as im:
+@pytest.mark.parametrize(
+    "filename",
+    ("Tests/images/apng/split_fdat.png", "Tests/images/apng/split_fdat_zero_chunk.png"),
+)
+def test_apng_fdat(filename):
+    with Image.open(filename) as im:
         im.seek(im.n_frames - 1)
         assert im.getpixel((0, 0)) == (0, 255, 0, 255)
         assert im.getpixel((64, 32)) == (0, 255, 0, 255)

Tests/test_file_eps.py

@@ -124,14 +124,6 @@ def test_file_object(tmp_path):
             image1.save(fh, "EPS")
 
 
-@pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
-def test_iobase_object(tmp_path):
-    # issue 479
-    with Image.open(FILE1) as image1:
-        with open(str(tmp_path / "temp_iobase.eps"), "wb") as fh:
-            image1.save(fh, "EPS")
-
-
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
 def test_bytesio_object():
     with open(FILE1, "rb") as f:
@@ -203,25 +195,23 @@ def test_render_scale2():
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
-def test_resize():
-    files = [FILE1, FILE2, "Tests/images/illu10_preview.eps"]
-    for fn in files:
-        with Image.open(fn) as im:
-            new_size = (100, 100)
-            im = im.resize(new_size)
-            assert im.size == new_size
+@pytest.mark.parametrize("filename", (FILE1, FILE2, "Tests/images/illu10_preview.eps"))
+def test_resize(filename):
+    with Image.open(filename) as im:
+        new_size = (100, 100)
+        im = im.resize(new_size)
+        assert im.size == new_size
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")
-def test_thumbnail():
+@pytest.mark.parametrize("filename", (FILE1, FILE2))
+def test_thumbnail(filename):
     # Issue #619
     # Arrange
-    files = [FILE1, FILE2]
-    for fn in files:
-        with Image.open(FILE1) as im:
-            new_size = (100, 100)
-            im.thumbnail(new_size)
-            assert max(im.size) == max(new_size)
+    with Image.open(filename) as im:
+        new_size = (100, 100)
+        im.thumbnail(new_size)
+        assert max(im.size) == max(new_size)
 
 
 def test_read_binary_preview():
@@ -266,20 +256,19 @@ def _test_readline_file_psfile(test_string, ending):
         _test_readline_file_psfile(s, ending)
 
 
-def test_open_eps():
-    # https://github.com/python-pillow/Pillow/issues/1104
-    # Arrange
-    FILES = [
+@pytest.mark.parametrize(
+    "filename",
+    (
         "Tests/images/illu10_no_preview.eps",
         "Tests/images/illu10_preview.eps",
         "Tests/images/illuCS6_no_preview.eps",
         "Tests/images/illuCS6_preview.eps",
-    ]
-
-    # Act / Assert
-    for filename in FILES:
-        with Image.open(filename) as img:
-            assert img.mode == "RGB"
+    ),
+)
+def test_open_eps(filename):
+    # https://github.com/python-pillow/Pillow/issues/1104
+    with Image.open(filename) as img:
+        assert img.mode == "RGB"
 
 
 @pytest.mark.skipif(not HAS_GHOSTSCRIPT, reason="Ghostscript not available")

Tests/test_file_gif.py

@@ -793,24 +793,24 @@ def test_identical_frames(tmp_path):
         assert reread.info["duration"] == 4500
 
 
-def test_identical_frames_to_single_frame(tmp_path):
-    for duration in ([1000, 1500, 2000, 4000], (1000, 1500, 2000, 4000), 8500):
-        out = str(tmp_path / "temp.gif")
-        im_list = [
-            Image.new("L", (100, 100), "#000"),
-            Image.new("L", (100, 100), "#000"),
-            Image.new("L", (100, 100), "#000"),
-        ]
-
-        im_list[0].save(
-            out, save_all=True, append_images=im_list[1:], duration=duration
-        )
-        with Image.open(out) as reread:
-            # Assert that all frames were combined
-            assert reread.n_frames == 1
+@pytest.mark.parametrize(
+    "duration", ([1000, 1500, 2000, 4000], (1000, 1500, 2000, 4000), 8500)
+)
+def test_identical_frames_to_single_frame(duration, tmp_path):
+    out = str(tmp_path / "temp.gif")
+    im_list = [
+        Image.new("L", (100, 100), "#000"),
+        Image.new("L", (100, 100), "#000"),
+        Image.new("L", (100, 100), "#000"),
+    ]
 
-            # Assert that the new duration is the total of the identical frames
-            assert reread.info["duration"] == 8500
+    im_list[0].save(out, save_all=True, append_images=im_list[1:], duration=duration)
+    with Image.open(out) as reread:
+        # Assert that all frames were combined
+        assert reread.n_frames == 1
+
+        # Assert that the new duration is the total of the identical frames
+        assert reread.info["duration"] == 8500
 
 
 def test_number_of_loops(tmp_path):

Tests/test_file_jpeg.py

@@ -150,27 +150,30 @@ def test_icc(self, tmp_path):
             assert not im1.info.get("icc_profile")
             assert im2.info.get("icc_profile")
 
-    def test_icc_big(self):
+    @pytest.mark.parametrize(
+        "n",
+        (
+            0,
+            1,
+            3,
+            4,
+            5,
+            65533 - 14,  # full JPEG marker block
+            65533 - 14 + 1,  # full block plus one byte
+            ImageFile.MAXBLOCK,  # full buffer block
+            ImageFile.MAXBLOCK + 1,  # full buffer block plus one byte
+            ImageFile.MAXBLOCK * 4 + 3,  # large block
+        ),
+    )
+    def test_icc_big(self, n):
         # Make sure that the "extra" support handles large blocks
-        def test(n):
-            # The ICC APP marker can store 65519 bytes per marker, so
-            # using a 4-byte test code should allow us to detect out of
-            # order issues.
-            icc_profile = (b"Test" * int(n / 4 + 1))[:n]
-            assert len(icc_profile) == n  # sanity
-            im1 = self.roundtrip(hopper(), icc_profile=icc_profile)
-            assert im1.info.get("icc_profile") == (icc_profile or None)
-
-        test(0)
-        test(1)
-        test(3)
-        test(4)
-        test(5)
-        test(65533 - 14)  # full JPEG marker block
-        test(65533 - 14 + 1)  # full block plus one byte
-        test(ImageFile.MAXBLOCK)  # full buffer block
-        test(ImageFile.MAXBLOCK + 1)  # full buffer block plus one byte
-        test(ImageFile.MAXBLOCK * 4 + 3)  # large block
+        # The ICC APP marker can store 65519 bytes per marker, so
+        # using a 4-byte test code should allow us to detect out of
+        # order issues.
+        icc_profile = (b"Test" * int(n / 4 + 1))[:n]
+        assert len(icc_profile) == n  # sanity
+        im1 = self.roundtrip(hopper(), icc_profile=icc_profile)
+        assert im1.info.get("icc_profile") == (icc_profile or None)
 
     @mark_if_feature_version(
         pytest.mark.valgrind_known_error, "libjpeg_turbo", "2.0", reason="Known Failing"
@@ -649,19 +652,19 @@ def test_bad_mpo_header(self):
             # Assert
             assert im.format == "JPEG"
 
-    def test_save_correct_modes(self):
+    @pytest.mark.parametrize("mode", ("1", "L", "RGB", "RGBX", "CMYK", "YCbCr"))
+    def test_save_correct_modes(self, mode):
         out = BytesIO()
-        for mode in ["1", "L", "RGB", "RGBX", "CMYK", "YCbCr"]:
-            img = Image.new(mode, (20, 20))
-            img.save(out, "JPEG")
+        img = Image.new(mode, (20, 20))
+        img.save(out, "JPEG")
 
-    def test_save_wrong_modes(self):
+    @pytest.mark.parametrize("mode", ("LA", "La", "RGBA", "RGBa", "P"))
+    def test_save_wrong_modes(self, mode):
         # ref https://github.com/python-pillow/Pillow/issues/2005
         out = BytesIO()
-        for mode in ["LA", "La", "RGBA", "RGBa", "P"]:
-            img = Image.new(mode, (20, 20))
-            with pytest.raises(OSError):
-                img.save(out, "JPEG")
+        img = Image.new(mode, (20, 20))
+        with pytest.raises(OSError):
+            img.save(out, "JPEG")
 
     def test_save_tiff_with_dpi(self, tmp_path):
         # Arrange

Tests/test_file_jpeg2k.py

@@ -126,14 +126,14 @@ def test_prog_res_rt():
     assert_image_equal(im, test_card)
 
 
-def test_default_num_resolutions():
-    for num_resolutions in range(2, 6):
-        d = 1 << (num_resolutions - 1)
-        im = test_card.resize((d - 1, d - 1))
-        with pytest.raises(OSError):
-            roundtrip(im, num_resolutions=num_resolutions)
-        reloaded = roundtrip(im)
-        assert_image_equal(im, reloaded)
+@pytest.mark.parametrize("num_resolutions", range(2, 6))
+def test_default_num_resolutions(num_resolutions):
+    d = 1 << (num_resolutions - 1)
+    im = test_card.resize((d - 1, d - 1))
+    with pytest.raises(OSError):
+        roundtrip(im, num_resolutions=num_resolutions)
+    reloaded = roundtrip(im)
+    assert_image_equal(im, reloaded)
 
 
 def test_reduce():
@@ -266,14 +266,11 @@ def test_rgba():
             assert jp2.mode == "RGBA"
 
 
-def test_16bit_monochrome_has_correct_mode():
-    with Image.open("Tests/images/16bit.cropped.j2k") as j2k:
-        j2k.load()
-        assert j2k.mode == "I;16"
-
-    with Image.open("Tests/images/16bit.cropped.jp2") as jp2:
-        jp2.load()
-        assert jp2.mode == "I;16"
+@pytest.mark.parametrize("ext", (".j2k", ".jp2"))
+def test_16bit_monochrome_has_correct_mode(ext):
+    with Image.open("Tests/images/16bit.cropped" + ext) as im:
+        im.load()
+        assert im.mode == "I;16"
 
 
 def test_16bit_monochrome_jp2_like_tiff():

Tests/test_file_libtiff.py

@@ -509,20 +509,13 @@ def test_palette_save(self, im, tmp_path):
             # colormap/palette tag
             assert len(reloaded.tag_v2[320]) == 768
 
-    def xtest_bw_compression_w_rgb(self, tmp_path):
-        """This test passes, but when running all tests causes a failure due
-        to output on stderr from the error thrown by libtiff. We need to
-        capture that but not now"""
-
+    @pytest.mark.parametrize("compression", ("tiff_ccitt", "group3", "group4"))
+    def test_bw_compression_w_rgb(self, compression, tmp_path):
         im = hopper("RGB")
         out = str(tmp_path / "temp.tif")
 
         with pytest.raises(OSError):
-            im.save(out, compression="tiff_ccitt")
-        with pytest.raises(OSError):
-            im.save(out, compression="group3")
-        with pytest.raises(OSError):
-            im.save(out, compression="group4")
+            im.save(out, compression=compression)
 
     def test_fp_leak(self):
         im = Image.open("Tests/images/hopper_g4_500.tif")

Tests/test_file_palm.py

@@ -63,19 +63,7 @@ def test_p_mode(tmp_path):
     roundtrip(tmp_path, mode)
 
 
-def test_l_oserror(tmp_path):
-    # Arrange
-    mode = "L"
-
-    # Act / Assert
-    with pytest.raises(OSError):
-        helper_save_as_palm(tmp_path, mode)
-
-
-def test_rgb_oserror(tmp_path):
-    # Arrange
-    mode = "RGB"
-
-    # Act / Assert
+@pytest.mark.parametrize("mode", ("L", "RGB"))
+def test_oserror(tmp_path, mode):
     with pytest.raises(OSError):
         helper_save_as_palm(tmp_path, mode)

Tests/test_file_pcx.py

@@ -39,14 +39,14 @@ def test_invalid_file():
         PcxImagePlugin.PcxImageFile(invalid_file)
 
 
-def test_odd(tmp_path):
+@pytest.mark.parametrize("mode", ("1", "L", "P", "RGB"))
+def test_odd(tmp_path, mode):
     # See issue #523, odd sized images should have a stride that's even.
     # Not that ImageMagick or GIMP write PCX that way.
     # We were not handling properly.
-    for mode in ("1", "L", "P", "RGB"):
-        # larger, odd sized images are better here to ensure that
-        # we handle interrupted scan lines properly.
-        _roundtrip(tmp_path, hopper(mode).resize((511, 511)))
+    # larger, odd sized images are better here to ensure that
+    # we handle interrupted scan lines properly.
+    _roundtrip(tmp_path, hopper(mode).resize((511, 511)))
 
 
 def test_odd_read():