diff --git a/swh/core/tests/test_utils.py b/swh/core/tests/test_utils.py
new file mode 100644
index 0000000..1475eaa
--- /dev/null
+++ b/swh/core/tests/test_utils.py
@@ -0,0 +1,25 @@
+# Copyright (C) 2015-2016  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+import unittest
+
+from nose.tools import istest
+
+from swh.core import utils
+
+
+class UtilsTest(unittest.TestCase):
+    @istest
+    def grouper(self):
+        # given
+        gen = (d for d in [0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
+
+        # when
+        actual_group = []
+        for data in utils.grouper(gen, 3):
+            actual_group.append(list(data))
+
+        # then
+        self.assertEquals(actual_group, [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9]])
diff --git a/swh/core/utils.py b/swh/core/utils.py
new file mode 100644
index 0000000..0559d96
--- /dev/null
+++ b/swh/core/utils.py
@@ -0,0 +1,26 @@
+# Copyright (C) 2015-2016  The Software Heritage developers
+# See the AUTHORS file at the top-level directory of this distribution
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+
+import itertools
+
+
+def grouper(iterable, n):
+    """Collect data into fixed-length chunks or blocks.
+    The last block is exactly the size of the remaining data.
+
+    Args:
+        iterable: an iterable
+        n: size of block
+
+    Returns:
+        fixed-length chunks of blocks as iterables (except for the last
+        one which can be of size < n)
+
+    """
+    args = [iter(iterable)] * n
+    fv = None
+    for _data in itertools.zip_longest(*args, fillvalue=fv):
+        yield (d for d in _data if d is not fv)