Add unit test for org.osbuild.grub2.legacy

For now, test the content of /etc/default/grub configuration file.

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

stages/test/test_grub2_legacy.py

@@ -0,0 +1,38 @@
+#!/usr/bin/python3
+
+import os.path
+
+STAGE_NAME = "org.osbuild.grub2.legacy"
+
+
+# Test that the /etc/default/grub file is created with the correct content
+def test_grub2_default_conf(tmp_path, stage_module):
+    treedir = tmp_path / "tree"
+    confpath = treedir / "etc/default/grub"
+    confpath.parent.mkdir(parents=True, exist_ok=True)
+
+    options = {
+        "rootfs": {
+            "label": "root"
+        },
+        "entries": [
+            {
+                "id": "fff",
+                "kernel": "4.18",
+                "product": {
+                    "name": "Fedora",
+                    "version": "40"
+                }
+            }
+        ]
+    }
+
+    stage_module.main(treedir, options)
+    assert os.path.exists(confpath)
+    assert confpath.read_text() == """GRUB_TIMEOUT=0
+GRUB_CMDLINE_LINUX=""
+GRUB_DISABLE_SUBMENU=true
+GRUB_DISABLE_RECOVERY=true
+GRUB_TIMEOUT_STYLE=countdown
+GRUB_DEFAULT=saved
+"""