stages(org.osbuild.systemd.unit.create): add small unit test

Small unit test for the new `org.systemd.unit.create` stage. It
will do basic schema validation checks and ensures that a simple
service definition is correctly translated to a systemd unit.

stages/test/test_systemd_unit_create.py

@@ -0,0 +1,100 @@
+#!/usr/bin/python3
+
+import os
+import os.path
+import textwrap
+
+import pytest
+
+from osbuild import testutil
+
+STAGE_NAME = "org.osbuild.systemd.unit.create"
+
+
+@pytest.mark.parametrize("test_data,expected_err", [
+    # good
+    (
+        {
+            "filename": "foo.service",
+            "config": {
+                "Unit": {},
+                "Service": {},
+                "Install": {},
+            },
+        }, ""),
+    # bad
+    ({"config": {"Unit": {}, "Service": {}, "Install": {}}}, "'filename' is a required property"),
+    ({"filename": "foo.service"}, "'config' is a required property"),
+    ({"filename": "foo.service", "config": {"Service": {}, "Install": {}}},
+     "'Unit' is a required property"),
+    ({"filename": "foo.service", "config": {"Unit": {}, "Install": {}}},
+     "'Service' is a required property"),
+    ({"filename": "foo.service", "config": {"Unit": {}, "Service": {}}},
+     "'Install' is a required property"),
+])
+@pytest.mark.parametrize("stage_schema", ["1"], indirect=True)
+def test_schema_validation(stage_schema, test_data, expected_err):
+    test_input = {
+        "name": STAGE_NAME,
+        "options": test_data,
+    }
+    res = stage_schema.validate(test_input)
+    if expected_err == "":
+        assert res.valid is True, f"err: {[e.as_dict() for e in res.errors]}"
+    else:
+        assert res.valid is False
+        testutil.assert_jsonschema_error_contains(res, expected_err, expected_num_errs=1)
+
+
+def test_systemd_unit_create_simple(tmp_path, stage_module):
+    options = {
+        "filename": "create-directory.service",
+        "config": {
+            "Unit": {
+                "Description": "Create directory",
+                "DefaultDependencies": False,
+                "ConditionPathExists": [
+                    "|!/etc/myfile"
+                ]
+            },
+            "Service": {
+                "Type": "oneshot",
+                "RemainAfterExit": True,
+                "ExecStart": [
+                    "mkdir -p /etc/mydir",
+                    "touch /etc/myfile"
+                ]
+            },
+            "Install": {
+                "WantedBy": [
+                    "local-fs.target"
+                ],
+                "RequiredBy": [
+                    "multi-user.target"
+                ]
+            }
+        }
+    }
+    expected_unit_path = tmp_path / "usr/lib/systemd/system/create-directory.service"
+    # should the stage create the dir?
+    expected_unit_path.parent.mkdir(parents=True)
+
+    stage_module.main(tmp_path, options)
+    assert os.path.exists(expected_unit_path)
+    assert expected_unit_path.read_text(encoding="utf-8") == textwrap.dedent("""\
+    [Unit]
+    Description=Create directory
+    DefaultDependencies=False
+    ConditionPathExists=|!/etc/myfile
+
+    [Service]
+    Type=oneshot
+    RemainAfterExit=True
+    ExecStart=mkdir -p /etc/mydir
+    ExecStart=touch /etc/myfile
+
+    [Install]
+    WantedBy=local-fs.target
+    RequiredBy=multi-user.target
+
+    """)