test(env): check each distro's parent image against its own reference

The loop test only required three different parent images for three distros,
which a swap between two of them would still pass. Each iteration now also
records the owner and tag it sees, and its image must equal
pkgmgr_image(distro, owner, tag). With the loader of main the test fails on
arch with pkgmgr-debian:stable.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/unit/python/scripts/tests/deploy/test_distros.py

@@ -20,6 +20,7 @@ import unittest
 from pathlib import Path
 
 from utils.cache.files import PROJECT_ROOT, read_text
+from utils.distros import pkgmgr_image
 from utils.env.parser import parse_static_env
 
 LOOP = PROJECT_ROOT / "scripts" / "tests" / "deploy" / "distros.sh"
@@ -79,13 +80,15 @@ class TestDistrosLoop(unittest.TestCase):
     def test_every_distro_runs_with_a_parent_image_of_its_own(self) -> None:
         proc, record = self._run(
             DISTROS,
-            'echo "${INFINITO_DISTRO} ${INFINITO_PARENT_IMAGE}" >> "${RECORD}"',
+            'echo "${INFINITO_DISTRO} ${INFINITO_PARENT_IMAGE}'
+            ' ${INFINITO_PARENT_IMAGE_OWNER} ${INFINITO_PARENT_IMAGE_TAG}" >> "${RECORD}"',
             INFINITO_CI_DISTRO_BUDGET_SECONDS="600",
         )
         self.assertEqual(proc.returncode, 0, proc.stderr)
-        images = dict(line.split() for line in record.splitlines())
-        self.assertEqual(sorted(images), sorted(DISTROS.split()))
-        self.assertEqual(len(set(images.values())), len(images), images)
+        rows = [line.split() for line in record.splitlines()]
+        self.assertEqual(sorted(row[0] for row in rows), sorted(DISTROS.split()))
+        for distro, image, owner, tag in rows:
+            self.assertEqual(image, pkgmgr_image(distro, owner=owner, tag=tag))
 
     def test_the_command_inherits_the_env_layer(self) -> None:
         proc, record = self._run(