diff --git a/Tests/helper.py b/Tests/helper.py
index 769a34377..e4b1d917c 100644
--- a/Tests/helper.py
+++ b/Tests/helper.py
@@ -178,31 +178,6 @@ class PillowTestCase(unittest.TestCase):
         except OSError:
             pass  # report?
 
-    def assert_warning(self, warn_class, func, *args, **kwargs):
-        import warnings
-
-        with warnings.catch_warnings(record=True) as w:
-            # Cause all warnings to always be triggered.
-            warnings.simplefilter("always")
-
-            # Hopefully trigger a warning.
-            result = func(*args, **kwargs)
-
-            # Verify some things.
-            if warn_class is None:
-                self.assertEqual(
-                    len(w), 0, "Expected no warnings, got %s" % [v.category for v in w]
-                )
-            else:
-                self.assertGreaterEqual(len(w), 1)
-                found = False
-                for v in w:
-                    if issubclass(v.category, warn_class):
-                        found = True
-                        break
-                self.assertTrue(found)
-        return result
-
     def tempfile(self, template):
         assert template[:5] in ("temp.", "temp_")
         fd, path = tempfile.mkstemp(template[4:], template[:4])
diff --git a/Tests/test_bmp_reference.py b/Tests/test_bmp_reference.py
index c493c7852..c4fe25910 100644
--- a/Tests/test_bmp_reference.py
+++ b/Tests/test_bmp_reference.py
@@ -1,5 +1,6 @@
 import os
 
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, assert_image_similar
@@ -28,7 +29,7 @@ class TestBmpReference(PillowTestCase):
                     pass
 
             # Assert that there is no unclosed file warning
-            self.assert_warning(None, open, f)
+            pytest.warns(None, open, f)
 
     def test_questionable(self):
         """ These shouldn't crash/dos, but it's not well defined that these
diff --git a/Tests/test_core_resources.py b/Tests/test_core_resources.py
index 9dd8bd065..22563b92a 100644
--- a/Tests/test_core_resources.py
+++ b/Tests/test_core_resources.py
@@ -1,6 +1,7 @@
 import sys
 import unittest
 
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, is_pypy
@@ -169,12 +170,12 @@ class TestEnvVars(PillowTestCase):
         self.assertEqual(Image.core.get_block_size(), 2 * 1024 * 1024)
 
     def test_warnings(self):
-        self.assert_warning(
+        pytest.warns(
             UserWarning, Image._apply_env_variables, {"PILLOW_ALIGNMENT": "15"}
         )
-        self.assert_warning(
+        pytest.warns(
             UserWarning, Image._apply_env_variables, {"PILLOW_BLOCK_SIZE": "1024"}
         )
-        self.assert_warning(
+        pytest.warns(
             UserWarning, Image._apply_env_variables, {"PILLOW_BLOCKS_MAX": "wat"}
         )
diff --git a/Tests/test_decompression_bomb.py b/Tests/test_decompression_bomb.py
index 5d0d37099..e55cf23dc 100644
--- a/Tests/test_decompression_bomb.py
+++ b/Tests/test_decompression_bomb.py
@@ -1,3 +1,4 @@
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, hopper
@@ -38,7 +39,7 @@ class TestDecompressionBomb(PillowTestCase):
             with Image.open(TEST_FILE):
                 pass
 
-        self.assert_warning(Image.DecompressionBombWarning, open)
+        pytest.warns(Image.DecompressionBombWarning, open)
 
     def test_exception(self):
         # Set limit to trigger exception on the test file
@@ -71,7 +72,7 @@ class TestDecompressionCrop(PillowTestCase):
         # Crops can extend the extents, therefore we should have the
         # same decompression bomb warnings on them.
         box = (0, 0, self.src.width * 2, self.src.height * 2)
-        self.assert_warning(Image.DecompressionBombWarning, self.src.crop, box)
+        pytest.warns(Image.DecompressionBombWarning, self.src.crop, box)
 
     def test_crop_decompression_checks(self):
 
@@ -87,7 +88,7 @@ class TestDecompressionCrop(PillowTestCase):
             self.assertEqual(im.crop(value).size, (9, 9))
 
         for value in warning_values:
-            self.assert_warning(Image.DecompressionBombWarning, im.crop, value)
+            pytest.warns(Image.DecompressionBombWarning, im.crop, value)
 
         for value in error_values:
             with self.assertRaises(Image.DecompressionBombError):
diff --git a/Tests/test_file_dcx.py b/Tests/test_file_dcx.py
index 23bab5356..36f46299c 100644
--- a/Tests/test_file_dcx.py
+++ b/Tests/test_file_dcx.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import DcxImagePlugin, Image
 
 from .helper import PillowTestCase, assert_image_equal, hopper, is_pypy
@@ -27,7 +28,7 @@ class TestFileDcx(PillowTestCase):
             im = Image.open(TEST_FILE)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -35,14 +36,14 @@ class TestFileDcx(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(TEST_FILE) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_invalid_file(self):
         with open("Tests/images/flower.jpg", "rb") as fp:
diff --git a/Tests/test_file_fli.py b/Tests/test_file_fli.py
index d6779a457..45c0fd1a1 100644
--- a/Tests/test_file_fli.py
+++ b/Tests/test_file_fli.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import FliImagePlugin, Image
 
 from .helper import PillowTestCase, assert_image_equal, is_pypy
@@ -34,7 +35,7 @@ class TestFileFli(PillowTestCase):
             im = Image.open(static_test_file)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -42,14 +43,14 @@ class TestFileFli(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(static_test_file) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_tell(self):
         # Arrange
diff --git a/Tests/test_file_gif.py b/Tests/test_file_gif.py
index 0709a66a6..d9226cdba 100644
--- a/Tests/test_file_gif.py
+++ b/Tests/test_file_gif.py
@@ -1,6 +1,7 @@
 import unittest
 from io import BytesIO
 
+import pytest
 from PIL import GifImagePlugin, Image, ImageDraw, ImagePalette
 
 from .helper import (
@@ -47,7 +48,7 @@ class TestFileGif(PillowTestCase):
             im = Image.open(TEST_GIF)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -55,14 +56,14 @@ class TestFileGif(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(TEST_GIF) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_invalid_file(self):
         invalid_file = "Tests/images/flower.jpg"
@@ -684,7 +685,7 @@ class TestFileGif(PillowTestCase):
         # Single frame
         im = Image.new("RGB", (1, 1))
         im.info["transparency"] = (255, 0, 0)
-        self.assert_warning(UserWarning, im.save, out)
+        pytest.warns(UserWarning, im.save, out)
 
         with Image.open(out) as reloaded:
             self.assertNotIn("transparency", reloaded.info)
@@ -693,7 +694,7 @@ class TestFileGif(PillowTestCase):
         im = Image.new("RGB", (1, 1))
         im.info["transparency"] = b""
         ims = [Image.new("RGB", (1, 1))]
-        self.assert_warning(UserWarning, im.save, out, save_all=True, append_images=ims)
+        pytest.warns(UserWarning, im.save, out, save_all=True, append_images=ims)
 
         with Image.open(out) as reloaded:
             self.assertNotIn("transparency", reloaded.info)
diff --git a/Tests/test_file_icns.py b/Tests/test_file_icns.py
index 5a1d958fc..5693a19fd 100644
--- a/Tests/test_file_icns.py
+++ b/Tests/test_file_icns.py
@@ -2,6 +2,7 @@ import io
 import sys
 import unittest
 
+import pytest
 from PIL import IcnsImagePlugin, Image
 
 from .helper import PillowTestCase, assert_image_equal, assert_image_similar
@@ -19,7 +20,7 @@ class TestFileIcns(PillowTestCase):
         with Image.open(TEST_FILE) as im:
 
             # Assert that there is no unclosed file warning
-            self.assert_warning(None, im.load)
+            pytest.warns(None, im.load)
 
             self.assertEqual(im.mode, "RGBA")
             self.assertEqual(im.size, (1024, 1024))
diff --git a/Tests/test_file_ico.py b/Tests/test_file_ico.py
index 9e0a78256..47fae7ed9 100644
--- a/Tests/test_file_ico.py
+++ b/Tests/test_file_ico.py
@@ -1,5 +1,6 @@
 import io
 
+import pytest
 from PIL import IcoImagePlugin, Image, ImageDraw
 
 from .helper import PillowTestCase, assert_image_equal, hopper
@@ -87,7 +88,7 @@ class TestFileIco(PillowTestCase):
             with Image.open("Tests/images/hopper_unexpected.ico") as im:
                 self.assertEqual(im.size, (16, 16))
 
-        self.assert_warning(UserWarning, open)
+        pytest.warns(UserWarning, open)
 
     def test_draw_reloaded(self):
         with Image.open(TEST_ICO_FILE) as im:
diff --git a/Tests/test_file_im.py b/Tests/test_file_im.py
index 66f4e7be1..ec046020e 100644
--- a/Tests/test_file_im.py
+++ b/Tests/test_file_im.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import Image, ImImagePlugin
 
 from .helper import PillowTestCase, assert_image_equal, hopper, is_pypy
@@ -22,7 +23,7 @@ class TestFileIm(PillowTestCase):
             im = Image.open(TEST_IM)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -30,14 +31,14 @@ class TestFileIm(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(TEST_IM) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_tell(self):
         # Arrange
diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index 92ffa586f..eb623b408 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -1,6 +1,7 @@
 import os
 from io import BytesIO
 
+import pytest
 from PIL import Image, ImageFile, JpegImagePlugin
 
 from .helper import (
@@ -531,7 +532,7 @@ class TestFileJpeg(PillowTestCase):
         # Act
         # Shouldn't raise error
         fn = "Tests/images/sugarshack_bad_mpo_header.jpg"
-        with self.assert_warning(UserWarning, Image.open, fn) as im:
+        with pytest.warns(UserWarning, Image.open, fn) as im:
 
             # Assert
             self.assertEqual(im.format, "JPEG")
diff --git a/Tests/test_file_mpo.py b/Tests/test_file_mpo.py
index 12405294e..5ed1bb75e 100644
--- a/Tests/test_file_mpo.py
+++ b/Tests/test_file_mpo.py
@@ -1,6 +1,7 @@
 import unittest
 from io import BytesIO
 
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, assert_image_similar, is_pypy
@@ -38,7 +39,7 @@ class TestFileMpo(PillowTestCase):
             im = Image.open(test_files[0])
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -46,14 +47,14 @@ class TestFileMpo(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(test_files[0]) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_app(self):
         for test_file in test_files:
diff --git a/Tests/test_file_png.py b/Tests/test_file_png.py
index cf878f33b..a3d3c0897 100644
--- a/Tests/test_file_png.py
+++ b/Tests/test_file_png.py
@@ -338,7 +338,7 @@ class TestFilePng(PillowTestCase):
 
         with Image.open(TEST_PNG_FILE) as im:
             # Assert that there is no unclosed file warning
-            self.assert_warning(None, im.verify)
+            pytest.warns(None, im.verify)
 
         with Image.open(TEST_PNG_FILE) as im:
             im.load()
diff --git a/Tests/test_file_psd.py b/Tests/test_file_psd.py
index a5eb9aa61..e77964d32 100644
--- a/Tests/test_file_psd.py
+++ b/Tests/test_file_psd.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import Image, PsdImagePlugin
 
 from .helper import PillowTestCase, assert_image_similar, hopper, is_pypy
@@ -24,7 +25,7 @@ class TestImagePsd(PillowTestCase):
             im = Image.open(test_file)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -32,14 +33,14 @@ class TestImagePsd(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(test_file) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_invalid_file(self):
         invalid_file = "Tests/images/flower.jpg"
diff --git a/Tests/test_file_spider.py b/Tests/test_file_spider.py
index c2ced2a9f..243b5e466 100644
--- a/Tests/test_file_spider.py
+++ b/Tests/test_file_spider.py
@@ -2,6 +2,7 @@ import tempfile
 import unittest
 from io import BytesIO
 
+import pytest
 from PIL import Image, ImageSequence, SpiderImagePlugin
 
 from .helper import PillowTestCase, assert_image_equal, hopper, is_pypy
@@ -23,7 +24,7 @@ class TestImageSpider(PillowTestCase):
             im = Image.open(TEST_FILE)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -31,14 +32,14 @@ class TestImageSpider(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open(TEST_FILE) as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_save(self):
         # Arrange
diff --git a/Tests/test_file_tar.py b/Tests/test_file_tar.py
index a77e4e84c..240f7acba 100644
--- a/Tests/test_file_tar.py
+++ b/Tests/test_file_tar.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import Image, TarIO
 
 from .helper import PillowTestCase, is_pypy
@@ -33,18 +34,18 @@ class TestFileTar(PillowTestCase):
         def open():
             TarIO.TarIO(TEST_TAR_FILE, "hopper.jpg")
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_close(self):
         def open():
             tar = TarIO.TarIO(TEST_TAR_FILE, "hopper.jpg")
             tar.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_contextmanager(self):
         def open():
             with TarIO.TarIO(TEST_TAR_FILE, "hopper.jpg"):
                 pass
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
diff --git a/Tests/test_file_tga.py b/Tests/test_file_tga.py
index 8a446028d..61d8e7efe 100644
--- a/Tests/test_file_tga.py
+++ b/Tests/test_file_tga.py
@@ -2,6 +2,7 @@ import os
 from glob import glob
 from itertools import product
 
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, assert_image_equal, hopper
@@ -136,7 +137,7 @@ class TestFileTga(PillowTestCase):
 
         # Save with custom id section greater than 255 characters
         id_section = b"Test content" * 25
-        self.assert_warning(UserWarning, lambda: im.save(out, id_section=id_section))
+        pytest.warns(UserWarning, lambda: im.save(out, id_section=id_section))
         with Image.open(out) as test_im:
             self.assertEqual(test_im.info["id_section"], id_section[:255])
 
diff --git a/Tests/test_file_tiff.py b/Tests/test_file_tiff.py
index d415f29ee..8140fa3fe 100644
--- a/Tests/test_file_tiff.py
+++ b/Tests/test_file_tiff.py
@@ -60,7 +60,7 @@ class TestFileTiff(PillowTestCase):
             im = Image.open("Tests/images/multipage.tiff")
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
@@ -68,14 +68,14 @@ class TestFileTiff(PillowTestCase):
             im.load()
             im.close()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_context_manager(self):
         def open():
             with Image.open("Tests/images/multipage.tiff") as im:
                 im.load()
 
-        self.assert_warning(None, open)
+        pytest.warns(None, open)
 
     def test_mac_tiff(self):
         # Read RGBa images from macOS [@PIL136]
@@ -185,7 +185,7 @@ class TestFileTiff(PillowTestCase):
     def test_bad_exif(self):
         with Image.open("Tests/images/hopper_bad_exif.jpg") as i:
             # Should not raise struct.error.
-            self.assert_warning(UserWarning, i._getexif)
+            pytest.warns(UserWarning, i._getexif)
 
     def test_save_rgba(self):
         im = hopper("RGBA")
diff --git a/Tests/test_file_tiff_metadata.py b/Tests/test_file_tiff_metadata.py
index a46b09aaf..e46e94668 100644
--- a/Tests/test_file_tiff_metadata.py
+++ b/Tests/test_file_tiff_metadata.py
@@ -1,6 +1,7 @@
 import io
 import struct
 
+import pytest
 from PIL import Image, TiffImagePlugin, TiffTags
 from PIL.TiffImagePlugin import IFDRational
 
@@ -174,7 +175,7 @@ class TestFileTiffMetadata(PillowTestCase):
         head = f.read(8)
         info = TiffImagePlugin.ImageFileDirectory(head)
         # Should not raise struct.error.
-        self.assert_warning(UserWarning, info.load, f)
+        pytest.warns(UserWarning, info.load, f)
 
     def test_iccprofile(self):
         # https://github.com/python-pillow/Pillow/issues/1462
@@ -333,4 +334,4 @@ class TestFileTiffMetadata(PillowTestCase):
         ifd.tagtype[277] = TiffTags.SHORT
 
         # Should not raise ValueError.
-        self.assert_warning(UserWarning, lambda: ifd[277])
+        pytest.warns(UserWarning, lambda: ifd[277])
diff --git a/Tests/test_file_webp.py b/Tests/test_file_webp.py
index 16ed14ce1..81742c659 100644
--- a/Tests/test_file_webp.py
+++ b/Tests/test_file_webp.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import Image, WebPImagePlugin
 
 from .helper import (
@@ -23,7 +24,7 @@ class TestUnsupportedWebp(PillowTestCase):
             WebPImagePlugin.SUPPORTED = False
 
         file_path = "Tests/images/hopper.webp"
-        self.assert_warning(
+        pytest.warns(
             UserWarning, lambda: self.assertRaises(IOError, Image.open, file_path)
         )
 
@@ -146,7 +147,7 @@ class TestFileWebp(PillowTestCase):
         file_path = "Tests/images/hopper.webp"
         with Image.open(file_path) as image:
             temp_file = self.tempfile("temp.webp")
-            self.assert_warning(None, image.save, temp_file)
+            pytest.warns(None, image.save, temp_file)
 
     def test_file_pointer_could_be_reused(self):
         file_path = "Tests/images/hopper.webp"
diff --git a/Tests/test_image.py b/Tests/test_image.py
index 2cddd604f..334e330f4 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -4,6 +4,7 @@ import shutil
 import tempfile
 import unittest
 
+import pytest
 from PIL import Image, UnidentifiedImageError
 
 from .helper import (
@@ -576,7 +577,7 @@ class TestImage(PillowTestCase):
 
         # Act/Assert
         with Image.open(test_file) as im:
-            self.assert_warning(None, im.save, temp_file)
+            pytest.warns(None, im.save, temp_file)
 
     def test_load_on_nonexclusive_multiframe(self):
         with open("Tests/images/frozenpond.mpo", "rb") as fp:
diff --git a/Tests/test_image_convert.py b/Tests/test_image_convert.py
index 53f872d2f..b7355a3ad 100644
--- a/Tests/test_image_convert.py
+++ b/Tests/test_image_convert.py
@@ -1,3 +1,4 @@
+import pytest
 from PIL import Image
 
 from .helper import (
@@ -122,7 +123,7 @@ class TestImageConvert(PillowTestCase):
         self.assertIn("transparency", im_p.info)
         im_p.save(f)
 
-        im_p = self.assert_warning(UserWarning, im.convert, "P", palette=Image.ADAPTIVE)
+        im_p = pytest.warns(UserWarning, im.convert, "P", palette=Image.ADAPTIVE)
         self.assertNotIn("transparency", im_p.info)
         im_p.save(f)
 
@@ -144,7 +145,7 @@ class TestImageConvert(PillowTestCase):
         self.assertNotIn("transparency", im_rgba.info)
         im_rgba.save(f)
 
-        im_p = self.assert_warning(UserWarning, im.convert, "P", palette=Image.ADAPTIVE)
+        im_p = pytest.warns(UserWarning, im.convert, "P", palette=Image.ADAPTIVE)
         self.assertNotIn("transparency", im_p.info)
         im_p.save(f)
 
diff --git a/Tests/test_imagecms.py b/Tests/test_imagecms.py
index 07aa26692..ba704f4c8 100644
--- a/Tests/test_imagecms.py
+++ b/Tests/test_imagecms.py
@@ -2,6 +2,7 @@ import datetime
 import os
 from io import BytesIO
 
+import pytest
 from PIL import Image, ImageMode
 
 from .helper import (
@@ -447,7 +448,7 @@ class TestImageCms(PillowTestCase):
         p = o.profile
 
         def helper_deprecated(attr, expected):
-            result = self.assert_warning(DeprecationWarning, getattr, p, attr)
+            result = pytest.warns(DeprecationWarning, getattr, p, attr)
             self.assertEqual(result, expected)
 
         # p.color_space
diff --git a/Tests/test_numpy.py b/Tests/test_numpy.py
index 19ed76591..45fabee78 100644
--- a/Tests/test_numpy.py
+++ b/Tests/test_numpy.py
@@ -1,5 +1,6 @@
 import unittest
 
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, assert_deep_equal, assert_image, hopper
@@ -220,4 +221,4 @@ class TestNumpy(PillowTestCase):
         with Image.open(test_file) as im:
 
             # Act/Assert
-            self.assert_warning(None, lambda: array(im))
+            pytest.warns(None, lambda: array(im))