From 9a3d554c1d38ec23fe3180458793098518d3cf2f Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Fri, 8 Jun 2018 19:17:48 +1000
Subject: [PATCH] Changed Exception tests to be more specific

---
 Tests/test_file_jpeg.py      | 12 ++++++------
 Tests/test_file_tiff.py      |  2 +-
 Tests/test_image_quantize.py |  2 +-
 Tests/test_imagemorph.py     | 37 ++++++++++++++++++++++++++++--------
 4 files changed, 37 insertions(+), 16 deletions(-)

diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index e7e639f05..9804c2676 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -439,17 +439,17 @@ class TestFileJpeg(PillowTestCase):
         self._n_qtables_helper(4, "Tests/images/pil_sample_cmyk.jpg")
 
         # not a sequence
-        self.assertRaises(Exception, self.roundtrip, im, qtables='a')
+        self.assertRaises(ValueError, self.roundtrip, im, qtables='a')
         # sequence wrong length
-        self.assertRaises(Exception, self.roundtrip, im, qtables=[])
+        self.assertRaises(ValueError, self.roundtrip, im, qtables=[])
         # sequence wrong length
-        self.assertRaises(Exception,
+        self.assertRaises(ValueError,
                           self.roundtrip, im, qtables=[1, 2, 3, 4, 5])
 
         # qtable entry not a sequence
-        self.assertRaises(Exception, self.roundtrip, im, qtables=[1])
+        self.assertRaises(ValueError, self.roundtrip, im, qtables=[1])
         # qtable entry has wrong number of items
-        self.assertRaises(Exception,
+        self.assertRaises(ValueError,
                           self.roundtrip, im, qtables=[[1, 2, 3, 4]])
 
     @unittest.skipUnless(djpeg_available(), "djpeg not available")
@@ -599,7 +599,7 @@ class TestFileCloseW32(PillowTestCase):
         im = Image.open(tmpfile)
         fp = im.fp
         self.assertFalse(fp.closed)
-        self.assertRaises(Exception, os.remove, tmpfile)
+        self.assertRaises(WindowsError, os.remove, tmpfile)
         im.load()
         self.assertTrue(fp.closed)
         # this should not fail, as load should have closed the file.
diff --git a/Tests/test_file_tiff.py b/Tests/test_file_tiff.py
index 3d63e084d..aac845e0f 100644
--- a/Tests/test_file_tiff.py
+++ b/Tests/test_file_tiff.py
@@ -505,7 +505,7 @@ class TestFileTiffW32(PillowTestCase):
         im = Image.open(tmpfile)
         fp = im.fp
         self.assertFalse(fp.closed)
-        self.assertRaises(Exception, os.remove, tmpfile)
+        self.assertRaises(WindowsError, os.remove, tmpfile)
         im.load()
         self.assertTrue(fp.closed)
 
diff --git a/Tests/test_image_quantize.py b/Tests/test_image_quantize.py
index 6a9ff1187..5b10d2de3 100644
--- a/Tests/test_image_quantize.py
+++ b/Tests/test_image_quantize.py
@@ -39,7 +39,7 @@ class TestImageQuantize(PillowTestCase):
     def test_rgba_quantize(self):
         image = hopper('RGBA')
         image.quantize()
-        self.assertRaises(Exception, image.quantize, method=0)
+        self.assertRaises(ValueError, image.quantize, method=0)
 
     def test_quantize(self):
         image = Image.open('Tests/images/caption_6_33_22.png').convert('RGB')
diff --git a/Tests/test_imagemorph.py b/Tests/test_imagemorph.py
index cad3caebd..83fa0b5a9 100644
--- a/Tests/test_imagemorph.py
+++ b/Tests/test_imagemorph.py
@@ -80,9 +80,15 @@ class MorphTests(PillowTestCase):
 
     def test_no_operator_loaded(self):
         mop = ImageMorph.MorphOp()
-        self.assertRaises(Exception, mop.apply, None)
-        self.assertRaises(Exception, mop.match, None)
-        self.assertRaises(Exception, mop.save_lut, None)
+        with self.assertRaises(Exception) as e:
+            mop.apply(None)
+        self.assertEqual(str(e.exception), 'No operator loaded')
+        with self.assertRaises(Exception) as e:
+            mop.match(None)
+        self.assertEqual(str(e.exception), 'No operator loaded')
+        with self.assertRaises(Exception) as e:
+            mop.save_lut(None)
+        self.assertEqual(str(e.exception), 'No operator loaded')
 
     # Test the named patterns
     def test_erosion8(self):
@@ -213,9 +219,18 @@ class MorphTests(PillowTestCase):
         im = hopper('RGB')
         mop = ImageMorph.MorphOp(op_name="erosion8")
 
-        self.assertRaises(Exception, mop.apply, im)
-        self.assertRaises(Exception, mop.match, im)
-        self.assertRaises(Exception, mop.get_on_pixels, im)
+        with self.assertRaises(Exception) as e:
+            mop.apply(im)
+        self.assertEqual(str(e.exception),
+                         'Image must be binary, meaning it must use mode L')
+        with self.assertRaises(Exception) as e:
+            mop.match(im)
+        self.assertEqual(str(e.exception),
+                         'Image must be binary, meaning it must use mode L')
+        with self.assertRaises(Exception) as e:
+            mop.get_on_pixels(im)
+        self.assertEqual(str(e.exception),
+                         'Image must be binary, meaning it must use mode L')
 
     def test_add_patterns(self):
         # Arrange
@@ -248,7 +263,10 @@ class MorphTests(PillowTestCase):
         lb.add_patterns(new_patterns)
 
         # Act / Assert
-        self.assertRaises(Exception, lb.build_lut)
+        with self.assertRaises(Exception) as e:
+            lb.build_lut()
+        self.assertEqual(str(e.exception),
+                         'Syntax error in pattern "a pattern with a syntax error"')
 
     def test_load_invalid_mrl(self):
         # Arrange
@@ -256,7 +274,10 @@ class MorphTests(PillowTestCase):
         mop = ImageMorph.MorphOp()
 
         # Act / Assert
-        self.assertRaises(Exception, mop.load_lut, invalid_mrl)
+        with self.assertRaises(Exception) as e:
+            mop.load_lut(invalid_mrl)
+        self.assertEqual(str(e.exception),
+                         'Wrong size operator file!')
 
     def test_roundtrip_mrl(self):
         # Arrange