tests: Reuse utils.sha256sum

The utility function was added in 08da7cc7, but it never was removed
from here.

1 files changed, 2 insertions, 8 deletions

diff --git a/tests/testutils/repo/tar.py b/tests/testutils/repo/tar.py
index b9cec97b6..158a04891 100644
--- a/tests/testutils/repo/tar.py
+++ b/tests/testutils/repo/tar.py
@@ -2,6 +2,8 @@ import os
 import tarfile
 import hashlib
 
+from buildstream.utils import sha256sum
+
 from .repo import Repo
 
 
@@ -30,11 +32,3 @@ class Tar(Repo):
             config['ref'] = ref
 
         return config
-
-
-def sha256sum(filename):
-    h = hashlib.sha256()
-    with open(filename, "rb") as f:
-        for chunk in iter(lambda: f.read(4096), b""):
-            h.update(chunk)
-    return h.hexdigest()