use skip_unless_feature in more tests

Author: nulano

Tests/test_image_reduce.py

@@ -1,7 +1,7 @@
 import pytest
 from PIL import Image, ImageMath, ImageMode
 
-from .helper import convert_to_comparable
+from .helper import convert_to_comparable, skip_unless_feature
 
 codecs = dir(Image.core)
 
@@ -254,9 +254,7 @@ def test_mode_F():
         compare_reduce_with_box(im, factor)
 
 
-@pytest.mark.skipif(
-    "jpeg2k_decoder" not in codecs, reason="JPEG 2000 support not available"
-)
+@skip_unless_feature("jpg_2000")
 def test_jpeg2k():
     with Image.open("Tests/images/test-card-lossless.jp2") as im:
         assert im.reduce(2).size == (320, 240)

Tests/test_imagegrab.py

@@ -4,7 +4,7 @@
 import pytest
 from PIL import Image, ImageGrab
 
-from .helper import assert_image
+from .helper import assert_image, skip_unless_feature
 
 
 class TestImageGrab:
@@ -22,7 +22,7 @@ def test_grab(self):
         im = ImageGrab.grab(bbox=(10, 20, 50, 80))
         assert_image(im, im.mode, (40, 60))
 
-    @pytest.mark.skipif(not Image.core.HAVE_XCB, reason="requires XCB")
+    @skip_unless_feature("xcb")
     def test_grab_x11(self):
         try:
             if sys.platform not in ("win32", "darwin"):
@@ -45,7 +45,7 @@ def test_grab_no_xcb(self):
             ImageGrab.grab(xdisplay="")
         assert str(e.value).startswith("Pillow was built without XCB support")
 
-    @pytest.mark.skipif(not Image.core.HAVE_XCB, reason="requires XCB")
+    @skip_unless_feature("xcb")
     def test_grab_invalid_xdisplay(self):
         with pytest.raises(OSError) as e:
             ImageGrab.grab(xdisplay="error.test:0.0")