stages: add new unit test for kickstart stage

This commit adds a simple and lightweight unit test for the new
kickstart options. It's pretty simple but also cheap and runs
fast.

stages/test/test_kickstart.py

@@ -0,0 +1,32 @@
+#!/usr/bin/python3
+
+import os.path
+
+import pytest
+
+from osbuild.testutil.imports import import_module_from_path
+
+
+@pytest.mark.parametrize("test_input,expected", [
+    ({"lang": "en_US.UTF-8"}, "lang en_US.UTF-8"),
+    ({"keyboard": "us"}, "keyboard us"),
+    ({"timezone": "UTC"}, "timezone UTC"),
+    ({"lang": "en_US.UTF-8",
+      "keyboard": "us",
+      "timezone": "UTC",
+      },
+     "lang en_US.UTF-8\nkeyboard us\ntimezone UTC"),
+])
+def test_kickstart(tmp_path, test_input, expected):
+    ks_stage_path = os.path.join(os.path.dirname(__file__), "../org.osbuild.kickstart")
+    ks_stage = import_module_from_path("ks_stage", ks_stage_path)
+
+    ks_path = "kickstart/kfs.cfg"
+    options = {"path": ks_path}
+    options.update(test_input)
+
+    ks_stage.main(tmp_path, options)
+
+    with open(os.path.join(tmp_path, ks_path), encoding="utf-8") as fp:
+        ks_content = fp.read()
+    assert ks_content == expected + "\n"