def METHOD_NAME(self):
    # This tests an object set that will have a copy operation
    # 2**20 in size.
    with self.get_pack(pack1_sha) as orig_pack:
        orig_blob = orig_pack[a_sha]
        new_blob = Blob()
        new_blob.data = orig_blob.data + (b"x" * 2 ** 20)
        new_blob_2 = Blob()
        new_blob_2.data = new_blob.data + b"y"
        all_to_pack = list(orig_pack.pack_tuples()) + [
            (new_blob, None),
            (new_blob_2, None),
        ]
        pack_path = os.path.join(self._tempdir, "pack_with_deltas")
        write_pack(pack_path, all_to_pack, deltify=True)
    output = run_git_or_fail(["verify-pack", "-v", pack_path])
    self.assertEqual(
        {x[0].id for x in all_to_pack},
        _git_verify_pack_object_list(output),
    )
    # We specifically made a new blob that should be a delta
    # against the blob a_sha, so make sure we really got only 3
    # non-delta objects:
    got_non_delta = int(_NON_DELTA_RE.search(output).group("non_delta"))
    self.assertEqual(
        3,
        got_non_delta,
        "Expected 3 non-delta objects, got %d" % got_non_delta,
    )
    # We expect one object to have a delta chain length of two
    # (new_blob_2), so let's verify that actually happens:
    self.assertIn(b"chain length = 2", output)