Implement legacy image portion of the data model

This also makes use of the newly created input system

data/registry_model/test/test_pre_oci_model.py

@@ -75,3 +75,44 @@ def test_create_manifest_label(pre_oci_model):
   found_manifest = pre_oci_model.get_manifest_for_tag(found_tag)
 
   pre_oci_model.create_manifest_label(found_manifest, 'foo', 'bar', 'internal')
+
+
+@pytest.mark.parametrize('repo_namespace, repo_name', [
+  ('devtable', 'simple'),
+  ('devtable', 'complex'),
+  ('devtable', 'history'),
+  ('buynlarge', 'orgrepo'),
+])
+def test_legacy_images(repo_namespace, repo_name, pre_oci_model):
+  repository_ref = pre_oci_model.lookup_repository(repo_namespace, repo_name)
+  legacy_images = pre_oci_model.get_legacy_images(repository_ref)
+  assert len(legacy_images)
+
+  found_tags = set()
+  for image in legacy_images:
+    found_image = pre_oci_model.get_legacy_image(repository_ref, image.docker_image_id,
+                                                 include_parents=True)
+
+    assert found_image.docker_image_id == image.docker_image_id
+    assert found_image.parents == image.parents
+
+    # Check that the tags list can be retrieved.
+    assert image.tags is not None
+    found_tags.update({tag.name for tag in image.tags})
+
+    # Check against the actual DB row.
+    model_image = model.image.get_image(repository_ref._db_id, found_image.docker_image_id)
+    assert model_image.id == found_image._db_id
+    assert ([pid for pid in model_image.ancestor_id_list()] ==
+            [p._db_id for p in found_image.parents])
+
+    # Try without parents and ensure it raises an exception.
+    found_image = pre_oci_model.get_legacy_image(repository_ref, image.docker_image_id,
+                                                 include_parents=False)
+    with pytest.raises(Exception):
+      assert not found_image.parents
+
+  assert found_tags
+
+  unknown = pre_oci_model.get_legacy_image(repository_ref, 'unknown', include_parents=True)
+  assert unknown is None