end to end test helper, more end to end tests for tiffs

Tests/helper.py

@@ -14,11 +14,22 @@ logger = logging.getLogger(__name__)
 
 
 HAS_UPLOADER = False
-try:
-    import test_image_results
-    HAS_UPLOADER = True
-except ImportError:
-    pass
+
+if os.environ.get('SHOW_ERRORS', None):
+    # local img.show for errors. 
+    HAS_UPLOADER=True
+    class test_image_results:
+        @classmethod
+        def upload(self, a, b):
+            a.show()
+            b.show()
+else:
+    try:
+        import test_image_results
+        HAS_UPLOADER = True
+    except ImportError:
+        pass
+
 
 
 def convert_to_comparable(a, b):
@@ -99,11 +110,17 @@ class PillowTestCase(unittest.TestCase):
                 try:
                     url = test_image_results.upload(a, b)
                     logger.error("Url for test images: %s" % url)
-                except:
+                except Exception as msg:
                     pass
 
             self.fail(msg or "got different content")
 
+    def assert_image_equal_tofile(self, a, filename, msg=None, mode=None):
+        with Image.open(filename) as img:
+            if mode:
+                img = img.convert(mode)
+            self.assert_image_equal(a, img, msg)
+            
     def assert_image_similar(self, a, b, epsilon, msg=None):
         epsilon = float(epsilon)
         self.assertEqual(
@@ -136,6 +153,12 @@ class PillowTestCase(unittest.TestCase):
                     pass
             raise e
 
+    def assert_image_similar_tofile(self, a, filename, epsilon, msg=None, mode=None):
+        with Image.open(filename) as img:
+            if mode:
+                img = img.convert(mode)
+            self.assert_image_similar(a, img, epsilon, msg)
+
     def assert_warning(self, warn_class, func, *args, **kwargs):
         import warnings
 

Tests/test_file_tiff.py

@@ -51,6 +51,8 @@ class TestFileTiff(PillowTestCase):
         self.assertEqual(im.tile, [('raw', (0, 0, 55, 43), 8, ('RGBa', 0, 1))])
         im.load()
 
+        self.assert_image_similar_tofile(im, "Tests/images/pil136.png", 1)
+
     def test_16bit_RGBa_tiff(self):
         im = Image.open("Tests/images/tiff_16bit_RGBa.tiff")
 
@@ -59,6 +61,8 @@ class TestFileTiff(PillowTestCase):
         self.assertEqual(im.tile, [('tiff_lzw', (0, 0, 100, 40), 50, 'RGBa;16B')])
         im.load()
 
+        self.assert_image_equal_tofile(im, "Tests/images/tiff_16bit_RGBa_target.png")
+
     def test_wrong_bits_per_sample(self):
         im = Image.open("Tests/images/tiff_wrong_bits_per_sample.tiff")
 
@@ -84,11 +88,15 @@ class TestFileTiff(PillowTestCase):
         )
         im.load()
 
+        self.assert_image_equal_tofile(im, "Tests/images/pil168.png")
+        
     def test_sampleformat(self):
         # https://github.com/python-pillow/Pillow/issues/1466
         im = Image.open("Tests/images/copyleft.tiff")
         self.assertEqual(im.mode, 'RGB')
 
+        self.assert_image_equal_tofile(im, "Tests/images/copyleft.png", mode='RGB')
+
     def test_set_legacy_api(self):
         with self.assertRaises(Exception):
             ImageFileDirectory_v2.legacy_api = None
@@ -221,12 +229,7 @@ class TestFileTiff(PillowTestCase):
         # imagemagick will auto scale so that a 12bit FFF is 16bit FFF0,
         # so we need to unshift so that the integer values are the same.
 
-        im2 = Image.open('Tests/images/12in16bit.tif')
-
-        logger.debug("%s", [img.getpixel((0, idx))
-                            for img in [im, im2] for idx in range(3)])
-
-        self.assert_image_equal(im, im2)
+        self.assert_image_equal_tofile(im, 'Tests/images/12in16bit.tif')
 
     def test_32bit_float(self):
         # Issue 614, specific 32-bit float format