stages(kickstart): add test for schema validation

Add functional/regression around the schema validation for the
kickstart stage. The goal is to ensure that the regexp matching
in the schema allows the expected uses and rejects clearly forbiddn
ones.

stages/test/test_kickstart.py

@@ -4,6 +4,7 @@
 
 import pytest
 
+import osbuild.meta
 from osbuild.testutil.imports import import_module_from_path
 
 
@@ -30,3 +31,41 @@ def test_kickstart(tmp_path, test_input, expected):
     with open(os.path.join(tmp_path, ks_path), encoding="utf-8") as fp:
         ks_content = fp.read()
     assert ks_content == expected + "\n"
+
+
+@pytest.mark.parametrize("test_data,expected_err", [
+    # BAD pattern, ensure some obvious ways to write arbitrary
+    # kickstart files will not work
+    ({"clearpart": {"disklabel": r"\n%pre\necho p0wnd"}}, r"p0wnd' does not match"),
+    ({"clearpart": {"drives": [" --spaces-dashes-not-allowed"]}}, "' --spaces-dashes-not-allowed' does not match"),
+    ({"clearpart": {"drives": ["\n%pre not allowed"]}}, "not allowed' does not match"),
+    ({"clearpart": {"list": ["\n%pre not allowed"]}}, "not allowed' does not match"),
+    ({"clearpart": {"disklabel": "\n%pre not allowed"}}, "not allowed' does not match"),
+    # GOOD pattern we want to keep working
+    ({"clearpart": {"drives": ["sd*|hd*|vda", "/dev/vdc"]}}, ""),
+    ({"clearpart": {"drives": ["disk/by-id/scsi-58095BEC5510947BE8C0360F604351918"]}}, ""),
+    ({"clearpart": {"list": ["sda2","sda3","sdb1"]}}, ""),
+])
+def test_schema_validation_smoke(test_data, expected_err):
+    name = "org.osbuild.kickstart"
+    root = os.path.join(os.path.dirname(__file__), "../..")
+    mod_info = osbuild.meta.ModuleInfo.load(root, "Stage", name)
+    schema = osbuild.meta.Schema(mod_info.get_schema(), name)
+
+    test_input = {
+        "name": "org.osbuild.kickstart",
+        "options": {
+            "path": "some-path",
+        }
+    }
+    test_input["options"].update(test_data)
+    res = schema.validate(test_input)
+
+    if expected_err == "":
+        assert res.valid == True
+    else:
+        assert res.valid == False
+        assert len(res.errors) == 1
+        err_msgs = [e.as_dict()["message"] for e in res.errors]
+        assert expected_err in err_msgs[0]
+