Add Delegation/DelegatednRole specific tests

Signed-off-by: Martin Vrachev <mvrachev@vmware.com>

Author: MVrachev

tests/test_api.py

@@ -28,7 +28,9 @@
     Timestamp,
     Targets,
     Key,
-    Role
+    Role,
+    Delegations,
+    DelegatedRole,
 )
 
 from tuf.api.serialization import (
@@ -328,7 +330,7 @@ def test_key_class(self):
                     "public": "edcd0a32a07dce33f7c7873aaffbff36d20ea30787574ead335eefd337e4dacd"
                 },
                 "scheme": "ed25519"
-                        },
+            },
         }
         for key_dict in keys.values():
             # Testing that the workflow of deserializing and serializing
@@ -422,6 +424,76 @@ def test_metadata_root(self):
         with self.assertRaises(KeyError):
             root.signed.remove_key('root', 'nosuchkey')
 
+    def test_delegated_role_class(self):
+        roles = [
+            {
+                "keyids": [
+                    "c8022fa1e9b9cb239a6b362bbdffa9649e61ad2cb699d2e4bc4fdf7930a0e64a"
+                ],
+                "name": "role1",
+                "paths": [
+                    "file3.txt"
+                ],
+                "terminating": False,
+                "threshold": 1
+            }
+        ]
+        for role in roles:
+            # Testing that the workflow of deserializing and serializing
+            # a delegation role dictionary doesn't change the content.
+            key_obj = DelegatedRole.from_dict(role.copy())
+            self.assertEqual(role, key_obj.to_dict())
+
+            # Test creating a DelegatedRole object with both "paths" and
+            # "path_hash_prefixes" set.
+            role["path_hash_prefixes"] = "foo"
+            with self.assertRaises(ValueError):
+                DelegatedRole.from_dict(role.copy())
+
+            # Test creating DelegatedRole only with "path_hash_prefixes"
+            del role["paths"]
+            DelegatedRole.from_dict(role.copy())
+            role["paths"] = "foo"
+
+            # Test creating DelegatedRole only with "paths"
+            del role["path_hash_prefixes"]
+            DelegatedRole.from_dict(role.copy())
+            role["path_hash_prefixes"] = "foo"
+
+            # Test creating DelegatedRole without "paths" and
+            # "path_hash_prefixes" set
+            del role["paths"]
+            del role["path_hash_prefixes"]
+            DelegatedRole.from_dict(role)
+
+
+    def test_delegation_class(self):
+        roles = [
+                {
+                    "keyids": [
+                        "c8022fa1e9b9cb239a6b362bbdffa9649e61ad2cb699d2e4bc4fdf7930a0e64a"
+                    ],
+                    "name": "role1",
+                    "paths": [
+                        "file3.txt"
+                    ],
+                    "terminating": False,
+                    "threshold": 1
+                }
+            ]
+        keys = {
+                "59a4df8af818e9ed7abe0764c0b47b4240952aa0d179b5b78346c470ac30278d":{
+                    "keytype": "ed25519",
+                    "keyval": {
+                        "public": "edcd0a32a07dce33f7c7873aaffbff36d20ea30787574ead335eefd337e4dacd"
+                    },
+                    "scheme": "ed25519"
+                },
+            }
+        delegations_dict = {"keys": keys, "roles": roles}
+        delegations = Delegations.from_dict(copy.deepcopy(delegations_dict))
+        self.assertEqual(delegations_dict, delegations.to_dict())
+
 
     def test_metadata_targets(self):
         targets_path = os.path.join(

tuf/api/metadata.py

@@ -775,10 +775,8 @@ def __init__(
                 "Only one of the attributes 'paths' and"
                 "'path_hash_prefixes' can be set!"
             )
-        if paths:
-            self.paths = paths
-        elif path_hash_prefixes:
-            self.path_hash_prefixes = path_hash_prefixes
+        self.paths = paths
+        self.path_hash_prefixes = path_hash_prefixes
 
     @classmethod
     def from_dict(cls, role_dict: Mapping[str, Any]) -> "Role":