stages: add test for the new org.grub2.iso.legacy stage

This commit adds a small smoke test that ensures our new
org.osbuild.grub2.iso.legacy stages does not regress easily.

stages/test/test_grub2_iso_legacy.py

@@ -0,0 +1,137 @@
+#!/usr/bin/python3
+
+import os.path
+from unittest.mock import call, patch
+
+import pytest
+
+STAGE_NAME = "org.osbuild.grub2.iso.legacy"
+
+expected_grub_cfg = """
+function load_video {
+  insmod all_video
+}
+
+load_video
+set gfxpayload=keep
+insmod gzio
+insmod part_gpt
+insmod ext2
+insmod chain
+
+set timeout=10
+### END /etc/grub.d/00_header ###
+
+search --no-floppy --set=root -l 'Fedora-41-X86_64'
+
+### BEGIN /etc/grub.d/10_linux ###
+menuentry 'Install Fedora-IoT 41' --class fedora --class gnu-linux --class gnu --class os {
+	linux /images/pxeboot/vmlinuz inst.ks=hd:LABEL=Fedora-41-X86_64:/install.ks quiet
+	initrd /images/pxeboot/initrd.img
+}
+menuentry 'Test this media & install Fedora-IoT 41' --class fedora --class gnu-linux --class gnu --class os {
+	linux /images/pxeboot/vmlinuz inst.ks=hd:LABEL=Fedora-41-X86_64:/install.ks rd.live.check quiet
+	initrd /images/pxeboot/initrd.img
+}
+submenu 'Troubleshooting -->' {
+	menuentry 'Install Fedora-IoT 41 in basic graphics mode' --class fedora --class gnu-linux --class gnu --class os {
+		linux /images/pxeboot/vmlinuz inst.ks=hd:LABEL=Fedora-41-X86_64:/install.ks nomodeset quiet
+		initrd /images/pxeboot/initrd.img
+	}
+	menuentry 'Rescue a Fedora-IoT system' --class fedora --class gnu-linux --class gnu --class os {
+		linux /images/pxeboot/vmlinuz inst.ks=hd:LABEL=Fedora-41-X86_64:/install.ks inst.rescue quiet
+		initrd /images/pxeboot/initrd.img
+	}
+	menuentry 'Boot first drive' --class fedora --class gnu-linux --class gnu --class os {
+		chainloader (hd0)+1
+	}
+}
+"""
+
+
+@patch("shutil.copytree")
+def test_grub2_iso_legacy_smoke(mocked_copytree, tmp_path, stage_module):
+    treedir = tmp_path / "tree"
+    confpath = treedir / "boot/grub2/grub.cfg"
+    confpath.parent.mkdir(parents=True, exist_ok=True)
+
+    # from fedora-ostree-bootiso-xz.json
+    options = {
+        "product": {
+            "name": "Fedora-IoT",
+            "version": "41"
+        },
+        "isolabel": "Fedora-41-X86_64",
+        "kernel": {
+            "dir": "/images/pxeboot",
+            "opts": [
+                "inst.ks=hd:LABEL=Fedora-41-X86_64:/install.ks"
+            ]
+        },
+        "config": {
+            "timeout": 10,
+        }
+    }
+
+    stage_module.main(treedir, options)
+
+    assert os.path.exists(confpath)
+    assert confpath.read_text() == expected_grub_cfg
+    assert mocked_copytree.call_args_list == [
+        call("/usr/lib/grub/i386-pc", os.fspath(treedir / "boot/grub2/i386-pc"),
+             dirs_exist_ok=True),
+    ]
+
+
+@pytest.mark.parametrize("test_data,expected_err", [
+    # bad
+    (
+        {}, ["'isolabel' is a required property", "'kernel' is a required property", "'product' is a required property"]
+    ),
+    (
+        {
+            "isolabel": "an-isolabel",
+            "product": {
+                "name": "a-name",
+                "version": "a-version",
+            },
+            "kernel": {},
+        }, ["'dir' is a required property"],
+    ),
+    (
+        {
+            "isolabel": "an-isolabel",
+            "product": {},
+            "kernel": {
+                "dir": "/path/to",
+            },
+        }, ["'name' is a required property", "'version' is a required property"],
+    ),
+    # good
+    (
+        {
+            "isolabel": "an-isolabel",
+            "product": {
+                "name": "a-name",
+                "version": "a-version",
+            },
+            "kernel": {
+                "dir": "/path/to",
+            },
+        }, "",
+    ),
+])
+def test_schema_validation(stage_schema, test_data, expected_err):
+    test_input = {
+        "type": STAGE_NAME,
+        "options": {},
+    }
+    test_input["options"].update(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
+        err_msgs = sorted([e.as_dict()["message"] for e in res.errors])
+        assert err_msgs == expected_err