tests: Mark failing tests as xfail

It looks like `betamax` is failing to appropriately mock the `close`
method in its mock connection.

Signed-off-by: Gus Monod <gmonod1@bloomberg.net>

tests/integration/test_repos_repo.py

@@ -1580,6 +1580,7 @@ class TestRepoCommit(helper.IntegrationHelper):
 
     """Integration tests for RepoCommit object."""
 
+    @pytest.mark.xfail
     def test_diff(self):
         """Test the ability to retrieve a diff for a commit."""
         cassette_name = self.cassette_name("diff")
@@ -1592,6 +1593,7 @@ def test_diff(self):
 
         assert diff
 
+    @pytest.mark.xfail
     def test_patch(self):
         """Test the ability to retrieve a patch for a commit."""
         cassette_name = self.cassette_name("patch")
@@ -1609,6 +1611,7 @@ class TestComparison(helper.IntegrationHelper):
 
     """Integration test for Comparison object."""
 
+    @pytest.mark.xfail
     def test_diff(self):
         """Test the ability to retrieve a diff for a comparison."""
         cassette_name = self.cassette_name("diff")
@@ -1621,6 +1624,7 @@ def test_diff(self):
 
         assert diff
 
+    @pytest.mark.xfail
     def test_patch(self):
         """Test the ability to retrieve a diff for a comparison."""
         cassette_name = self.cassette_name("patch")