test/fmt_v2: add simple check for input references

Specifically this test checks that the order given in the manifest is
preserved when loaded, i.e. the internal dict has the keys ordered in
the same way, independently in which way they were specified -- list
or object.

inputs/org.osbuild.ostree

@@ -36,6 +36,7 @@ SCHEMA = """
     "description": "Commit identifier",
     "oneOf": [{
       "type": "array",
+      "minItems": 1,
       "items": {
         "type": "string"
       }

test/mod/test_fmt_v2.py

@@ -135,6 +135,41 @@ BAD_REF_PIPELINE = {
 }
 
 
+INPUT_REFERENCES = {
+    "version": "2",
+    "sources": {
+        "org.osbuild.curl": {
+            "items": {
+                "sha256:6eeebf21f245bf0d6f58962dc49b6dfb51f55acb6a595c6b9cbe9628806b80a4":
+                "https://internet/curl-7.69.1-1.fc32.x86_64.rpm",
+                "sha256:184a0c274d4efa84a2f6d0a128aae87e2fa231fe9067b4a4dc8f886fa6f1dc18":
+                "https://internet/kernel-5.11.12-300.fc34.x86_64.rpm"
+            }
+        },
+    },
+    "pipelines": [
+        {
+            "name": "os",
+            "stages": [
+                {
+                    "type": "org.osbuild.rpm",
+                    "inputs": {
+                        "packages": {
+                            "type": "org.osbuild.files",
+                            "origin": "org.osbuild.source",
+                            "references": [
+                                "sha256:6eeebf21f245bf0d6f58962dc49b6dfb51f55acb6a595c6b9cbe9628806b80a4",
+                                "sha256:184a0c274d4efa84a2f6d0a128aae87e2fa231fe9067b4a4dc8f886fa6f1dc18"
+                            ]
+                        }
+                    }
+                }
+            ],
+        },
+    ]
+}
+
+
 class TestFormatV2(unittest.TestCase):
     def setUp(self):
         self.index = osbuild.meta.Index(os.curdir)
@@ -358,3 +393,49 @@ class TestFormatV2(unittest.TestCase):
         for check in itertools.permutations(devices.keys()):
             before = {name: devices[name] for name in check}
             ensure_sorted(fmt.sort_devices(before))
+
+    def check_input_references(self, desc):
+        info = self.index.detect_format_info(desc)
+        assert info, "Failed to detect format"
+
+        fmt = info.module
+        self.assertEqual(fmt.VERSION, "2")
+
+        res = fmt.validate(desc, self.index)
+        self.assert_validation(res)
+
+        manifest = fmt.load(desc, self.index)
+        self.assertIsNotNone(manifest)
+
+        pl = manifest.get("os")
+        assert pl is not None
+
+        packages = pl.stages[0].inputs["packages"]
+        assert packages is not None
+        assert len(packages.refs) == 2
+
+        refs = [
+            "sha256:6eeebf21f245bf0d6f58962dc49b6dfb51f55acb6a595c6b9cbe9628806b80a4",
+            "sha256:184a0c274d4efa84a2f6d0a128aae87e2fa231fe9067b4a4dc8f886fa6f1dc18"
+        ]
+
+        keys = list(packages.refs.keys())
+        assert keys == refs
+
+    def test_input_references(self):
+
+        # assert that the input references are ordered properly, i.e.
+        # their order is preserved as specified in the manifest
+
+        desc = INPUT_REFERENCES
+        self.check_input_references(desc)
+
+        inputs = desc["pipelines"][0]["stages"][0]["inputs"]["packages"]
+        refs = inputs["references"]
+
+        # check references as maps
+        inputs["references"] = {
+            k: {} for k in refs
+        }
+
+        self.check_input_references(desc)