Add support for GIT_DIFF_SHOW_BINARY

Adding the binary diff flag GIT_DIFF_SHOW_BINARY to pygit2.
libgit2 0.23.0 already supports this constant to be used in diff
flags and produces properly formated binary diffs.

src/pygit2.c

@@ -323,6 +323,7 @@ moduleinit(PyObject* m)
     ADD_CONSTANT_INT(m, GIT_DIFF_IGNORE_CASE)
     ADD_CONSTANT_INT(m, GIT_DIFF_SHOW_UNTRACKED_CONTENT)
     ADD_CONSTANT_INT(m, GIT_DIFF_SKIP_BINARY_CHECK)
+    ADD_CONSTANT_INT(m, GIT_DIFF_SHOW_BINARY)
     ADD_CONSTANT_INT(m, GIT_DIFF_INCLUDE_TYPECHANGE)
     ADD_CONSTANT_INT(m, GIT_DIFF_INCLUDE_TYPECHANGE_TREES)
     ADD_CONSTANT_INT(m, GIT_DIFF_RECURSE_IGNORED_DIRS)

test/test_diff.py

@@ -33,6 +33,7 @@ import unittest
 import pygit2
 from pygit2 import GIT_DIFF_INCLUDE_UNMODIFIED
 from pygit2 import GIT_DIFF_IGNORE_WHITESPACE, GIT_DIFF_IGNORE_WHITESPACE_EOL
+from pygit2 import GIT_DIFF_SHOW_BINARY
 from pygit2 import GIT_DELTA_RENAMED
 from . import utils
 from itertools import chain
@@ -63,6 +64,21 @@ index 297efb8..0000000
 -c/d contents
 """
 
+PATCH_BINARY = """diff --git a/binary_file b/binary_file
+index 86e5c10..b835d73 100644
+Binary files a/binary_file and b/binary_file differ
+"""
+
+PATCH_BINARY_SHOW = """diff --git a/binary_file b/binary_file
+index 86e5c1008b5ce635d3e3fffa4434c5eccd8f00b6..b835d73543244b6694f36a8c5dfdffb71b153db7 100644
+GIT binary patch
+literal 8
+Pc${NM%FIhFs^kIy3n&7R
+
+literal 8
+Pc${NM&PdElPvrst3ey5{
+"""
+
 DIFF_HEAD_TO_INDEX_EXPECTED = [
     'staged_changes',
     'staged_changes_file_deleted',
@@ -308,5 +324,15 @@ class DiffTest(utils.BareRepoTestCase):
                                  width=80)
         self.assertEqual(STATS_EXPECTED, formatted)
 
+
+class BinaryDiffTest(utils.BinaryFileRepoTestCase):
+    def test_binary_diff(self):
+        repo = self.repo
+        diff = repo.diff('HEAD', 'HEAD^')
+        self.assertEqual(PATCH_BINARY, diff.patch)
+        diff = repo.diff('HEAD', 'HEAD^', flags=GIT_DIFF_SHOW_BINARY)
+        self.assertEqual(PATCH_BINARY_SHOW, diff.patch)
+
+
 if __name__ == '__main__':
     unittest.main()

test/utils.py

@@ -160,6 +160,12 @@ class EmptyRepoTestCase(AutoRepoTestCase):
 
     repo_spec = 'tar', 'emptyrepo'
 
+
 class SubmoduleRepoTestCase(AutoRepoTestCase):
 
     repo_spec = 'tar', 'submodulerepo'
+
+
+class BinaryFileRepoTestCase(AutoRepoTestCase):
+
+    repo_spec = 'tar', 'binaryfilerepo'