From 7872501c5b3a5c64e84efad6d8128a9a5c11f3b7 Mon Sep 17 00:00:00 2001
From: Stephen Arthur <sarth@yelp.com>
Date: Sun, 22 May 2016 17:53:26 -0700
Subject: [PATCH] Added test cases to exhibit issues with custom qtables

---
 Tests/test_file_jpeg.py | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index 3b2e6cb20..dba16d346 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -303,6 +303,15 @@ class TestFileJpeg(PillowTestCase):
         filename = "Tests/images/junk_jpeg_header.jpg"
         Image.open(filename)
 
+    def _n_qtables_helper(self, n, test_file):
+        im = Image.open(test_file)
+        f = self.tempfile('temp.jpg')
+        im.save(f, qtables=[[n]*64]*n)
+        im = Image.open(f)
+        self.assertEqual(len(im.quantization), n)
+        reloaded = self.roundtrip(im, qtables="keep")
+        self.assertEqual(im.quantization, reloaded.quantization)
+
     def test_qtables(self):
         im = Image.open("Tests/images/hopper.jpg")
         qtables = im.quantization
@@ -359,6 +368,15 @@ class TestFileJpeg(PillowTestCase):
                                       1: standard_chrominance_qtable
                                   }), 30)
 
+        self._n_qtables_helper(1, "Tests/images/hopper_gray.jpg")
+        self._n_qtables_helper(1, "Tests/images/pil_sample_rgb.jpg")
+        self._n_qtables_helper(2, "Tests/images/pil_sample_rgb.jpg")
+        self._n_qtables_helper(3, "Tests/images/pil_sample_rgb.jpg")
+        self._n_qtables_helper(1, "Tests/images/pil_sample_cmyk.jpg")
+        self._n_qtables_helper(2, "Tests/images/pil_sample_cmyk.jpg")
+        self._n_qtables_helper(3, "Tests/images/pil_sample_cmyk.jpg")
+        self._n_qtables_helper(4, "Tests/images/pil_sample_cmyk.jpg")
+
         # not a sequence
         self.assertRaises(Exception, lambda: self.roundtrip(im, qtables='a'))
         # sequence wrong length