gnu: Add python-piexif.

* gnu/packages/python-xyz.scm (python-piexif): New variable.
* gnu/packages/patches/python-piexif-fix-tests-with-pillow-7.2.patch: New file.
* gnu/packages/python-xyz.scm (dist_patch_DATA): Add it.

1 files changed, 44 insertions, 0 deletions

diff --git a/gnu/packages/patches/python-piexif-fix-tests-with-pillow-7.2.patch b/gnu/packages/patches/python-piexif-fix-tests-with-pillow-7.2.patch
new file mode 100644
index 0000000000..caa2c47c08
--- /dev/null
+++ b/gnu/packages/patches/python-piexif-fix-tests-with-pillow-7.2.patch
@@ -0,0 +1,44 @@
+From 5209b53e9689ce28dcd045f384633378d619718f Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Jan=20Wi=C5=9Bniewski?= <vuko@vuko.pl>
+Date: Thu, 5 Nov 2020 16:18:52 +0100
+Subject: [PATCH] convert IFDRational to tuples in tests
+
+This fixes tests with Pillow version >= 7.2.0
+---
+ tests/s_test.py | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/tests/s_test.py b/tests/s_test.py
+index 5d105de..a7cad54 100644
+--- a/tests/s_test.py
++++ b/tests/s_test.py
+***************
+*** 9,14 ****
+--- 9,15 ----
+  import time
+  import unittest
+  
++ import PIL
+  from PIL import Image
+  import piexif
+  from piexif import _common, ImageIFD, ExifIFD, GPSIFD, TAGS, InvalidImageDataError
+***************
+*** 580,585 ****
+--- 581,597 ----
+  # test utility methods----------------------------------------------
+  
+      def _compare_value(self, v1, v2):
++         if isinstance(v2, PIL.TiffImagePlugin.IFDRational):
++             v2 = (v2.numerator, v2.denominator)
++         if isinstance(v2, tuple):
++             converted_v2 = []
++             for el in v2:
++                 if isinstance(el, PIL.TiffImagePlugin.IFDRational):
++                     converted_v2.append((el.numerator, el.denominator))
++                 else:
++                     converted_v2.append(el)
++             v2 = tuple(converted_v2)
++ 
+          if type(v1) != type(v2):
+              if isinstance(v1, tuple):
+                  self.assertEqual(pack_byte(*v1), v2)