Tests: Add system tests for groupadd in test_groupadd.py

tests/system/tests/test_groupadd.py

@@ -298,3 +298,41 @@ def test_groupadd__invalid_name(shadow: Shadow):
     if shadow.host.features["gshadow"]:
         gshadow_entry = shadow.tools.getent.gshadow("tgroup")
         assert gshadow_entry is None, "Group should not be found"
+
+
+@pytest.mark.topology(KnownTopology.Shadow)
+@pytest.mark.parametrize(
+    "lock_file",
+    [
+        pytest.param("/etc/group.lock", id="group_file"),
+        pytest.param("/etc/gshadow.lock", id="gshadow_file"),
+    ],
+)
+def test_groupadd__locked_file(shadow: Shadow, lock_file: str):
+    """
+    :title: Group creation fails when a lock file exists
+    :setup:
+        1. Create lock file
+    :steps:
+        1. Attempt to create group
+        2. Verify that groupadd command fails
+        3. Check group and gshadow entries
+    :expectedresults:
+        1. Group is not created
+        2. groupadd command fails with rc=10 (cannot lock file)
+        3. No group or gshadow entries are found
+    :customerscenario: False
+    """
+    shadow.fs.touch(lock_file)
+
+    with pytest.raises(ProcessError) as exc_info:
+        shadow.groupadd("tgroup")
+
+    assert exc_info.value.rc == 10, f"Expected rc=10 (cannot lock file), got {exc_info.value.rc}"
+
+    group_entry = shadow.tools.getent.group("tgroup")
+    assert group_entry is None, "Group should not be found"
+
+    if shadow.host.features["gshadow"]:
+        gshadow_entry = shadow.tools.getent.gshadow("tgroup")
+        assert gshadow_entry is None, "Group should not be found"