Replace PillowTestCase.assert_warning with pytest.warns

Author: hugovk

Tests/helper.py

@@ -178,31 +178,6 @@ def delete_tempfile(self, path):
         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])

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 @@ def open(f):
                     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

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 @@ def test_units(self):
         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"}
         )

Tests/test_decompression_bomb.py

@@ -1,3 +1,4 @@
+import pytest
 from PIL import Image
 
 from .helper import PillowTestCase, hopper
@@ -38,7 +39,7 @@ def open():
             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 @@ def testEnlargeCrop(self):
         # 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 @@ def test_crop_decompression_checks(self):
             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):

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
@@ -27,22 +28,22 @@ def open():
             im = Image.open(TEST_FILE)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
             im = Image.open(TEST_FILE)
             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:

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
@@ -34,22 +35,22 @@ def open():
             im = Image.open(static_test_file)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
             im = Image.open(static_test_file)
             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

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 (
@@ -47,22 +48,22 @@ def open():
             im = Image.open(TEST_GIF)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
             im = Image.open(TEST_GIF)
             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 @@ def test_rgb_transparency(self):
         # 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 @@ def test_rgb_transparency(self):
         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)

Tests/test_file_icns.py

@@ -2,6 +2,7 @@
 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 @@ def test_sanity(self):
         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))

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 @@ def open():
             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:

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
@@ -22,22 +23,22 @@ def open():
             im = Image.open(TEST_IM)
             im.load()
 
-        self.assert_warning(ResourceWarning, open)
+        pytest.warns(ResourceWarning, open)
 
     def test_closed_file(self):
         def open():
             im = Image.open(TEST_IM)
             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