Add test of calling salt.utils.user.get_group_dict

for the user having improper duplicate group

tests/pytests/functional/utils/user/test_get_group_dict.py

@@ -0,0 +1,24 @@
+import logging
+
+import pytest
+
+import salt.utils.platform
+import salt.utils.user
+from tests.support.mock import patch
+
+log = logging.getLogger(__name__)
+
+pytestmark = [
+    pytest.mark.skip_on_windows,
+]
+
+
+@pytest.mark.skip_on_platforms(
+    darwin=True,
+    freebsd=True,
+    reason="This test should not run on FreeBSD and Mac due to lack of duplicate GID support",
+)
+def test_get_group_dict_with_improper_duplicate_root_group():
+    with patch("salt.utils.user.get_group_list", return_value=["+", "root"]):
+        group_list = salt.utils.user.get_group_dict("root")
+        assert group_list == {"root": 0}