From 7e4fd9d84591a220d142cbc4652b18250984cf41 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Sun, 18 Apr 2021 14:47:05 +1000
Subject: [PATCH] Changed incorrect mode errors to ValueError

---
 Tests/test_imagemorph.py | 14 +++++++-------
 src/PIL/ImageMorph.py    |  6 +++---
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/Tests/test_imagemorph.py b/Tests/test_imagemorph.py
index eb41d2d08..368c2bba1 100644
--- a/Tests/test_imagemorph.py
+++ b/Tests/test_imagemorph.py
@@ -235,19 +235,19 @@ def test_negate():
     )
 
 
-def test_non_binary_images():
+def test_incorrect_mode():
     im = hopper("RGB")
     mop = ImageMorph.MorphOp(op_name="erosion8")
 
-    with pytest.raises(Exception) as e:
+    with pytest.raises(ValueError) as e:
         mop.apply(im)
-    assert str(e.value) == "Image must be binary, meaning it must use mode L"
-    with pytest.raises(Exception) as e:
+    assert str(e.value) == "Image mode must be L"
+    with pytest.raises(ValueError) as e:
         mop.match(im)
-    assert str(e.value) == "Image must be binary, meaning it must use mode L"
-    with pytest.raises(Exception) as e:
+    assert str(e.value) == "Image mode must be L"
+    with pytest.raises(ValueError) as e:
         mop.get_on_pixels(im)
-    assert str(e.value) == "Image must be binary, meaning it must use mode L"
+    assert str(e.value) == "Image mode must be L"
 
 
 def test_add_patterns():
diff --git a/src/PIL/ImageMorph.py b/src/PIL/ImageMorph.py
index b76dfa01f..fe0083754 100644
--- a/src/PIL/ImageMorph.py
+++ b/src/PIL/ImageMorph.py
@@ -196,7 +196,7 @@ class MorphOp:
             raise Exception("No operator loaded")
 
         if image.mode != "L":
-            raise Exception("Image must be binary, meaning it must use mode L")
+            raise ValueError("Image mode must be L")
         outimage = Image.new(image.mode, image.size, None)
         count = _imagingmorph.apply(bytes(self.lut), image.im.id, outimage.im.id)
         return count, outimage
@@ -211,7 +211,7 @@ class MorphOp:
             raise Exception("No operator loaded")
 
         if image.mode != "L":
-            raise Exception("Image must be binary, meaning it must use mode L")
+            raise ValueError("Image mode must be L")
         return _imagingmorph.match(bytes(self.lut), image.im.id)
 
     def get_on_pixels(self, image):
@@ -221,7 +221,7 @@ class MorphOp:
         of all matching pixels. See :ref:`coordinate-system`."""
 
         if image.mode != "L":
-            raise Exception("Image must be binary, meaning it must use mode L")
+            raise ValueError("Image mode must be L")
         return _imagingmorph.get_on_pixels(image.im.id)
 
     def load_lut(self, filename):