Use match argument

Tests/test_file_libtiff.py

@@ -1140,11 +1140,9 @@ def test_sampleformat_not_corrupted(self) -> None:
     def test_realloc_overflow(self, monkeypatch: pytest.MonkeyPatch) -> None:
         monkeypatch.setattr(TiffImagePlugin, "READ_LIBTIFF", True)
         with Image.open("Tests/images/tiff_overflow_rows_per_strip.tif") as im:
-            with pytest.raises(OSError) as e:
-                im.load()
-
             # Assert that the error code is IMAGING_CODEC_MEMORY
-            assert str(e.value) == "decoder error -9"
+            with pytest.raises(OSError, match="decoder error -9"):
+                im.load()
 
     @pytest.mark.parametrize("compression", ("tiff_adobe_deflate", "jpeg"))
     def test_save_multistrip(self, compression: str, tmp_path: Path) -> None:

Tests/test_file_ppm.py

@@ -293,25 +293,21 @@ def test_header_token_too_long(tmp_path: Path) -> None:
     with open(path, "wb") as f:
         f.write(b"P6\n 01234567890")
 
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="Token too long in file header: 01234567890"):
         with Image.open(path):
             pass
 
-    assert str(e.value) == "Token too long in file header: 01234567890"
-
 
 def test_truncated_file(tmp_path: Path) -> None:
     # Test EOF in header
     path = str(tmp_path / "temp.pgm")
     with open(path, "wb") as f:
         f.write(b"P6")
 
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="Reached EOF while reading header"):
         with Image.open(path):
             pass
 
-    assert str(e.value) == "Reached EOF while reading header"
-
     # Test EOF for PyDecoder
     fp = BytesIO(b"P5 3 1 4")
     with Image.open(fp) as im:
@@ -335,12 +331,12 @@ def test_invalid_maxval(maxval: bytes, tmp_path: Path) -> None:
     with open(path, "wb") as f:
         f.write(b"P6\n3 1 " + maxval)
 
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(
+        ValueError, match="maxval must be greater than 0 and less than 65536"
+    ):
         with Image.open(path):
             pass
 
-    assert str(e.value) == "maxval must be greater than 0 and less than 65536"
-
 
 def test_neg_ppm() -> None:
     # Storage.c accepted negative values for xsize, ysize.  the

Tests/test_file_tiff.py

@@ -134,9 +134,8 @@ def test_seek_too_large(self) -> None:
 
     def test_set_legacy_api(self) -> None:
         ifd = TiffImagePlugin.ImageFileDirectory_v2()
-        with pytest.raises(Exception) as e:
+        with pytest.raises(Exception, match="Not allowing setting of legacy api"):
             ifd.legacy_api = False
-        assert str(e.value) == "Not allowing setting of legacy api"
 
     def test_xyres_tiff(self) -> None:
         filename = "Tests/images/pil168.tif"

Tests/test_file_webp.py

@@ -154,9 +154,8 @@
     @pytest.mark.skipif(sys.maxsize <= 2**32, reason="Requires 64-bit system")
     def test_write_encoding_error_message(self, tmp_path: Path) -> None:
         im = Image.new("RGB", (15000, 15000))
-        with pytest.raises(ValueError) as e:
+        with pytest.raises(ValueError, match="encoding error 6"):
             im.save(tmp_path / "temp.webp", method=0)
-        assert str(e.value) == "encoding error 6"
 
     @pytest.mark.skipif(sys.maxsize <= 2**32, reason="Requires 64-bit system")
     def test_write_encoding_error_bad_dimension(self, tmp_path: Path) -> None:

Tests/test_image.py

@@ -65,9 +65,8 @@ def test_image_modes_success(self, mode: str) -> None:
 
     @pytest.mark.parametrize("mode", ("", "bad", "very very long"))
     def test_image_modes_fail(self, mode: str) -> None:
-        with pytest.raises(ValueError) as e:
+        with pytest.raises(ValueError, match="unrecognized image mode"):
             Image.new(mode, (1, 1))
-        assert str(e.value) == "unrecognized image mode"
 
     def test_exception_inheritance(self) -> None:
         assert issubclass(UnidentifiedImageError, OSError)

Tests/test_imagedraw.py

@@ -1626,7 +1626,7 @@ def test_compute_regular_polygon_vertices(
             0,
             ValueError,
             "bounding_circle should contain 2D coordinates "
-            "and a radius (e.g. (x, y, r) or ((x, y), r) )",
+            r"and a radius \(e.g. \(x, y, r\) or \(\(x, y\), r\) \)",
         ),
         (
             3,
@@ -1640,7 +1640,7 @@ def test_compute_regular_polygon_vertices(
             ((50, 50, 50), 25),
             0,
             ValueError,
-            "bounding_circle centre should contain 2D coordinates (e.g. (x, y))",
+            r"bounding_circle centre should contain 2D coordinates \(e.g. \(x, y\)\)",
         ),
         (
             3,
@@ -1665,9 +1665,8 @@ def test_compute_regular_polygon_vertices_input_error_handling(
     expected_error: type[Exception],
     error_message: str,
 ) -> None:
-    with pytest.raises(expected_error) as e:
+    with pytest.raises(expected_error, match=error_message):
         ImageDraw._compute_regular_polygon_vertices(bounding_circle, n_sides, rotation)  # type: ignore[arg-type]
-    assert str(e.value) == error_message
 
 
 def test_continuous_horizontal_edges_polygon() -> None:

Tests/test_imagefile.py

@@ -176,9 +176,8 @@ def test_truncated(self) -> None:
                 b"0" * ImageFile.SAFEBLOCK
             )  # only SAFEBLOCK bytes, so that the header is truncated
         )
-        with pytest.raises(OSError) as e:
+        with pytest.raises(OSError, match="Truncated File Read"):
             BmpImagePlugin.BmpImageFile(b)
-        assert str(e.value) == "Truncated File Read"
 
     @skip_unless_feature("zlib")
     def test_truncated_with_errors(self) -> None:

Tests/test_imagemorph.py

@@ -80,15 +80,12 @@ def test_lut(op: str) -> None:
 def test_no_operator_loaded() -> None:
     im = Image.new("L", (1, 1))
     mop = ImageMorph.MorphOp()
-    with pytest.raises(Exception) as e:
+    with pytest.raises(Exception, match="No operator loaded"):
         mop.apply(im)
-    assert str(e.value) == "No operator loaded"
-    with pytest.raises(Exception) as e:
+    with pytest.raises(Exception, match="No operator loaded"):
         mop.match(im)
-    assert str(e.value) == "No operator loaded"
-    with pytest.raises(Exception) as e:
+    with pytest.raises(Exception, match="No operator loaded"):
         mop.save_lut("")
-    assert str(e.value) == "No operator loaded"
 
 
 # Test the named patterns
@@ -238,15 +235,12 @@ def test_incorrect_mode() -> None:
     im = hopper("RGB")
     mop = ImageMorph.MorphOp(op_name="erosion8")
 
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="Image mode must be L"):
         mop.apply(im)
-    assert str(e.value) == "Image mode must be L"
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="Image mode must be L"):
         mop.match(im)
-    assert str(e.value) == "Image mode must be L"
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="Image mode must be L"):
         mop.get_on_pixels(im)
-    assert str(e.value) == "Image mode must be L"
 
 
 def test_add_patterns() -> None:
@@ -279,9 +273,10 @@ def test_pattern_syntax_error() -> None:
     lb.add_patterns(new_patterns)
 
     # Act / Assert
-    with pytest.raises(Exception) as e:
+    with pytest.raises(
+        Exception, match='Syntax error in pattern "a pattern with a syntax error"'
+    ):
         lb.build_lut()
-    assert str(e.value) == 'Syntax error in pattern "a pattern with a syntax error"'
 
 
 def test_load_invalid_mrl() -> None:
@@ -290,9 +285,8 @@ def test_load_invalid_mrl() -> None:
     mop = ImageMorph.MorphOp()
 
     # Act / Assert
-    with pytest.raises(Exception) as e:
+    with pytest.raises(Exception, match="Wrong size operator file!"):
         mop.load_lut(invalid_mrl)
-    assert str(e.value) == "Wrong size operator file!"
 
 
 def test_roundtrip_mrl(tmp_path: Path) -> None:

Tests/test_imagepath.py

@@ -81,13 +81,9 @@ def test_path_constructors(
 def test_invalid_path_constructors(
     coords: tuple[str, str] | Sequence[Sequence[int]],
 ) -> None:
-    # Act
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="incorrect coordinate type"):
         ImagePath.Path(coords)
 
-    # Assert
-    assert str(e.value) == "incorrect coordinate type"
-
 
 @pytest.mark.parametrize(
     "coords",
@@ -99,13 +95,9 @@ def test_invalid_path_constructors(
     ),
 )
 def test_path_odd_number_of_coordinates(coords: Sequence[int]) -> None:
-    # Act
-    with pytest.raises(ValueError) as e:
+    with pytest.raises(ValueError, match="wrong number of coordinates"):
         ImagePath.Path(coords)
 
-    # Assert
-    assert str(e.value) == "wrong number of coordinates"
-
 
 @pytest.mark.parametrize(
     "coords, expected",