diff --git a/swh/loader/core/tests/test_utils.py b/swh/loader/core/tests/test_utils.py
new file mode 100644
--- /dev/null
+++ b/swh/loader/core/tests/test_utils.py
@@ -0,0 +1,102 @@
+# Copyright (C) 2019  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 os
+
+from unittest.mock import patch
+
+from swh.loader.core.utils import clean_dangling_folders
+
+
+def prepare_arborescence_from(tmpdir, folder_names):
+    """Prepare arborescence tree with folders
+
+    Args:
+        tmpdir (Either[LocalPath, str]): Root temporary directory
+        folder_names (List[str]): List of folder names
+
+    Returns:
+        List of folders
+    """
+    dangling_folders = []
+    for dname in folder_names:
+        d = str(tmpdir / dname)
+        os.mkdir(d)
+        dangling_folders.append(d)
+    return str(tmpdir), dangling_folders
+
+
+def assert_dirs(actual_dirs, expected_dirs):
+    """Assert that the directory actual and expected match
+
+    """
+    for d in actual_dirs:
+        assert d in expected_dirs
+    assert len(actual_dirs) == len(expected_dirs)
+
+
+def test_clean_dangling_folders_0(tmpdir):
+    """Folder does not exist, do nothing"""
+    r = clean_dangling_folders('/path/does/not/exist', 'unused-pattern')
+    assert r is None
+
+
+@patch('swh.loader.core.utils.psutil.pid_exists', return_value=False)
+def test_clean_dangling_folders_1(mock_pid_exists, tmpdir):
+    """Folder which matches pattern with dead pid are cleaned up
+
+    """
+    rootpath, dangling = prepare_arborescence_from(tmpdir, [
+        'something',
+        'swh.loader.svn-4321.noisynoise',
+    ])
+
+    clean_dangling_folders(rootpath, 'swh.loader.svn')
+
+    actual_dirs = os.listdir(rootpath)
+    mock_pid_exists.assert_called_once_with(4321)
+    assert_dirs(actual_dirs, ['something'])
+
+
+@patch('swh.loader.core.utils.psutil.pid_exists', return_value=True)
+def test_clean_dangling_folders_2(mock_pid_exists, tmpdir):
+    """Folder which matches pattern with live pid are skipped
+
+    """
+    rootpath, dangling = prepare_arborescence_from(tmpdir, [
+        'something',
+        'swh.loader.hg-1234.noisynoise',
+    ])
+
+    clean_dangling_folders(rootpath, 'swh.loader.hg')
+
+    actual_dirs = os.listdir(rootpath)
+    mock_pid_exists.assert_called_once_with(1234)
+    assert_dirs(actual_dirs, [
+        'something', 'swh.loader.hg-1234.noisynoise',
+    ])
+
+
+@patch('swh.loader.core.utils.psutil.pid_exists',
+       return_value=False)
+@patch('swh.loader.core.utils.shutil.rmtree',
+       side_effect=ValueError('Could not remove for reasons'))
+def test_clean_dangling_folders_3(mock_rmtree, mock_pid_exists, tmpdir):
+    """Error in trying to clean dangling folders are skipped
+
+    """
+    path1 = 'thingy'
+    path2 = 'swh.loader.git-1468.noisy'
+    rootpath, dangling = prepare_arborescence_from(tmpdir, [
+        path1,
+        path2,
+    ])
+
+    clean_dangling_folders(rootpath, 'swh.loader.git')
+
+    actual_dirs = os.listdir(rootpath)
+    mock_pid_exists.assert_called_once_with(1468)
+    mock_rmtree.assert_called_once_with(os.path.join(rootpath, path2))
+    assert_dirs(actual_dirs, [path2, path1])