Apply top-level rolenames constants in tests

This applies the use of constants of top-level rolenames in the
tests instead of the previously hardcoded strings.
Addresses #1648

Signed-off-by: Ivana Atanasova <iyovcheva@iyovcheva-a02.vmware.com>

Author: Ivana Atanasova

tests/repository_simulator.py

@@ -59,7 +59,7 @@
 
 from tuf.api.metadata import (
     SPECIFICATION_VERSION,
-    TOP_LEVEL_ROLE_NAMES,
+    RoleNames,
     DelegatedRole,
     Delegations,
     Key,
@@ -73,6 +73,7 @@
     Timestamp,
 )
 from tuf.api.serialization.json import JSONSerializer
+from tuf.api.metadata import RoleNames
 from tuf.exceptions import FetcherHTTPError
 from tuf.ngclient.fetcher import FetcherInterface
 
@@ -140,7 +141,7 @@ def targets(self) -> Targets:
 
     def all_targets(self) -> Iterator[Tuple[str, Targets]]:
         """Yield role name and signed portion of targets one by one."""
-        yield "targets", self.md_targets.signed
+        yield RoleNames.TARGETS.value, self.md_targets.signed
         for role, md in self.md_delegates.items():
             yield role, md.signed
 
@@ -168,21 +169,21 @@ def _initialize(self):
         timestamp = Timestamp(1, SPEC_VER, self.safe_expiry, snapshot_meta)
         self.md_timestamp = Metadata(timestamp, OrderedDict())
 
-        roles = {role_name: Role([], 1) for role_name in TOP_LEVEL_ROLE_NAMES}
+        roles = {role_name.value: Role([], 1) for role_name in RoleNames}
         root = Root(1, SPEC_VER, self.safe_expiry, {}, roles, True)
 
-        for role in TOP_LEVEL_ROLE_NAMES:
+        for role in RoleNames:
             key, signer = self.create_key()
-            root.add_key(role, key)
-            self.add_signer(role, signer)
+            root.add_key(role.value, key)
+            self.add_signer(role.value, signer)
 
         self.md_root = Metadata(root, OrderedDict())
         self.publish_root()
 
     def publish_root(self):
         """Sign and store a new serialized version of root."""
         self.md_root.signatures.clear()
-        for signer in self.signers["root"].values():
+        for signer in self.signers[RoleNames.ROOT.value].values():
             self.md_root.sign(signer, append=True)
 
         self.signed_roots.append(self.md_root.to_bytes(JSONSerializer()))
@@ -198,9 +199,9 @@ def fetch(self, url: str) -> Iterator[bytes]:
         if path.startswith("/metadata/") and path.endswith(".json"):
             ver_and_name = path[len("/metadata/") :][: -len(".json")]
             # only consistent_snapshot supported ATM: timestamp is special case
-            if ver_and_name == "timestamp":
+            if ver_and_name == RoleNames.TIMESTAMP.value:
                 version = None
-                role = "timestamp"
+                role = RoleNames.TIMESTAMP.value
             else:
                 version, _, role = ver_and_name.partition(".")
                 version = int(version)
@@ -242,19 +243,19 @@ def _fetch_metadata(
 
         If version is None, non-versioned metadata is being requested.
         """
-        if role == "root":
+        if role == RoleNames.ROOT.value:
             # return a version previously serialized in publish_root()
             if version is None or version > len(self.signed_roots):
                 raise FetcherHTTPError(f"Unknown root version {version}", 404)
             logger.debug("fetched root version %d", version)
             return self.signed_roots[version - 1]
 
         # sign and serialize the requested metadata
-        if role == "timestamp":
+        if role == RoleNames.TIMESTAMP.value:
             md: Metadata = self.md_timestamp
-        elif role == "snapshot":
+        elif role == RoleNames.SNAPSHOT.value:
             md = self.md_snapshot
-        elif role == "targets":
+        elif role == RoleNames.TARGETS.value:
             md = self.md_targets
         else:
             md = self.md_delegates[role]
@@ -290,7 +291,7 @@ def update_timestamp(self):
         self.timestamp.snapshot_meta.version = self.snapshot.version
 
         if self.compute_metafile_hashes_length:
-            hashes, length = self._compute_hashes_and_length("snapshot")
+            hashes, length = self._compute_hashes_and_length(RoleNames.SNAPSHOT.value)
             self.timestamp.snapshot_meta.hashes = hashes
             self.timestamp.snapshot_meta.length = length
 
@@ -313,7 +314,7 @@ def update_snapshot(self):
 
     def add_target(self, role: str, data: bytes, path: str):
         """Create a target from data and add it to the target_files."""
-        if role == "targets":
+        if role == RoleNames.TARGETS.value:
             targets = self.targets
         else:
             targets = self.md_delegates[role].signed
@@ -332,7 +333,7 @@ def add_delegation(
         hash_prefixes: Optional[List[str]],
     ):
         """Add delegated target role to the repository."""
-        if delegator_name == "targets":
+        if delegator_name == RoleNames.TARGETS.value:
             delegator = self.targets
         else:
             delegator = self.md_delegates[delegator_name].signed
@@ -368,9 +369,9 @@ def write(self):
 
         for ver in range(1, len(self.signed_roots) + 1):
             with open(os.path.join(dest_dir, f"{ver}.root.json"), "wb") as f:
-                f.write(self._fetch_metadata("root", ver))
+                f.write(self._fetch_metadata(RoleNames.ROOT.value, ver))
 
-        for role in ["timestamp", "snapshot", "targets"]:
+        for role in [RoleNames.TIMESTAMP.value, RoleNames.SNAPSHOT.value, RoleNames.TARGETS.value]:
             with open(os.path.join(dest_dir, f"{role}.json"), "wb") as f:
                 f.write(self._fetch_metadata(role))
 

tests/test_api.py

@@ -39,6 +39,7 @@
 )
 from tuf.api.serialization import DeserializationError
 from tuf.api.serialization.json import CanonicalJSONSerializer, JSONSerializer
+from tuf.api.metadata import RoleNames
 
 logger = logging.getLogger(__name__)
 
@@ -70,7 +71,7 @@ def setUpClass(cls):
 
         # Load keys into memory
         cls.keystore = {}
-        for role in ["delegation", "snapshot", "targets", "timestamp"]:
+        for role in ["delegation", RoleNames.SNAPSHOT.value, RoleNames.TARGETS.value, RoleNames.TIMESTAMP.value]:
             cls.keystore[role] = import_ed25519_privatekey_from_file(
                 os.path.join(cls.keystore_dir, role + "_key"),
                 password="password",
@@ -84,10 +85,10 @@ def tearDownClass(cls):
 
     def test_generic_read(self):
         for metadata, inner_metadata_cls in [
-            ("root", Root),
-            ("snapshot", Snapshot),
-            ("timestamp", Timestamp),
-            ("targets", Targets),
+            (RoleNames.ROOT.value, Root),
+            (RoleNames.SNAPSHOT.value, Snapshot),
+            (RoleNames.TIMESTAMP.value, Timestamp),
+            (RoleNames.TARGETS.value, Targets),
         ]:
 
             # Load JSON-formatted metdata of each supported type from file
@@ -128,7 +129,7 @@ def test_compact_json(self):
         )
 
     def test_read_write_read_compare(self):
-        for metadata in ["root", "snapshot", "timestamp", "targets"]:
+        for metadata in [RoleNames.ROOT.value, RoleNames.SNAPSHOT.value, RoleNames.TIMESTAMP.value, RoleNames.TARGETS.value]:
             path = os.path.join(self.repo_dir, "metadata", metadata + ".json")
             md_obj = Metadata.from_file(path)
 
@@ -140,7 +141,7 @@ def test_read_write_read_compare(self):
             os.remove(path_2)
 
     def test_to_from_bytes(self):
-        for metadata in ["root", "snapshot", "timestamp", "targets"]:
+        for metadata in [RoleNames.ROOT.value, RoleNames.SNAPSHOT.value, RoleNames.TIMESTAMP.value, RoleNames.TARGETS.value]:
             path = os.path.join(self.repo_dir, "metadata", metadata + ".json")
             with open(path, "rb") as f:
                 metadata_bytes = f.read()
@@ -161,11 +162,11 @@ def test_sign_verify(self):
         root = Metadata[Root].from_file(root_path).signed
 
         # Locate the public keys we need from root
-        targets_keyid = next(iter(root.roles["targets"].keyids))
+        targets_keyid = next(iter(root.roles[RoleNames.TARGETS.value].keyids))
         targets_key = root.keys[targets_keyid]
-        snapshot_keyid = next(iter(root.roles["snapshot"].keyids))
+        snapshot_keyid = next(iter(root.roles[RoleNames.SNAPSHOT.value].keyids))
         snapshot_key = root.keys[snapshot_keyid]
-        timestamp_keyid = next(iter(root.roles["timestamp"].keyids))
+        timestamp_keyid = next(iter(root.roles[RoleNames.TIMESTAMP.value].keyids))
         timestamp_key = root.keys[timestamp_keyid]
 
         # Load sample metadata (targets) and assert ...
@@ -184,7 +185,7 @@ def test_sign_verify(self):
         with self.assertRaises(exceptions.UnsignedMetadataError):
             targets_key.verify_signature(md_obj, JSONSerializer())
 
-        sslib_signer = SSlibSigner(self.keystore["snapshot"])
+        sslib_signer = SSlibSigner(self.keystore[RoleNames.SNAPSHOT.value])
         # Append a new signature with the unrelated key and assert that ...
         sig = md_obj.sign(sslib_signer, append=True)
         # ... there are now two signatures, and
@@ -195,7 +196,7 @@ def test_sign_verify(self):
         # ... the returned (appended) signature is for snapshot key
         self.assertEqual(sig.keyid, snapshot_keyid)
 
-        sslib_signer = SSlibSigner(self.keystore["timestamp"])
+        sslib_signer = SSlibSigner(self.keystore[RoleNames.TIMESTAMP.value])
         # Create and assign (don't append) a new signature and assert that ...
         md_obj.sign(sslib_signer, append=False)
         # ... there now is only one signature,
@@ -210,7 +211,7 @@ def test_verify_failures(self):
         root = Metadata[Root].from_file(root_path).signed
 
         # Locate the timestamp public key we need from root
-        timestamp_keyid = next(iter(root.roles["timestamp"].keyids))
+        timestamp_keyid = next(iter(root.roles[RoleNames.TIMESTAMP.value].keyids))
         timestamp_key = root.keys[timestamp_keyid]
 
         # Load sample metadata (timestamp)
@@ -361,20 +362,20 @@ def test_metadata_verify_delegate(self):
         role2 = Metadata[Targets].from_file(role2_path)
 
         # test the expected delegation tree
-        root.verify_delegate("root", root)
-        root.verify_delegate("snapshot", snapshot)
-        root.verify_delegate("targets", targets)
+        root.verify_delegate(RoleNames.ROOT.value, root)
+        root.verify_delegate(RoleNames.SNAPSHOT.value, snapshot)
+        root.verify_delegate(RoleNames.TARGETS.value, targets)
         targets.verify_delegate("role1", role1)
         role1.verify_delegate("role2", role2)
 
         # only root and targets can verify delegates
         with self.assertRaises(TypeError):
-            snapshot.verify_delegate("snapshot", snapshot)
+            snapshot.verify_delegate(RoleNames.SNAPSHOT.value, snapshot)
         # verify fails for roles that are not delegated by delegator
         with self.assertRaises(ValueError):
             root.verify_delegate("role1", role1)
         with self.assertRaises(ValueError):
-            targets.verify_delegate("targets", targets)
+            targets.verify_delegate(RoleNames.TARGETS.value, targets)
         # verify fails when delegator has no delegations
         with self.assertRaises(ValueError):
             role2.verify_delegate("role1", role1)
@@ -383,31 +384,31 @@ def test_metadata_verify_delegate(self):
         expires = snapshot.signed.expires
         snapshot.signed.bump_expiration()
         with self.assertRaises(exceptions.UnsignedMetadataError):
-            root.verify_delegate("snapshot", snapshot)
+            root.verify_delegate(RoleNames.SNAPSHOT.value, snapshot)
         snapshot.signed.expires = expires
 
         # verify fails if roles keys do not sign the metadata
         with self.assertRaises(exceptions.UnsignedMetadataError):
-            root.verify_delegate("timestamp", snapshot)
+            root.verify_delegate(RoleNames.TIMESTAMP.value, snapshot)
 
         # Add a key to snapshot role, make sure the new sig fails to verify
-        ts_keyid = next(iter(root.signed.roles["timestamp"].keyids))
-        root.signed.add_key("snapshot", root.signed.keys[ts_keyid])
+        ts_keyid = next(iter(root.signed.roles[RoleNames.TIMESTAMP.value].keyids))
+        root.signed.add_key(RoleNames.SNAPSHOT.value, root.signed.keys[ts_keyid])
         snapshot.signatures[ts_keyid] = Signature(ts_keyid, "ff" * 64)
 
         # verify succeeds if threshold is reached even if some signatures
         # fail to verify
-        root.verify_delegate("snapshot", snapshot)
+        root.verify_delegate(RoleNames.SNAPSHOT.value, snapshot)
 
         # verify fails if threshold of signatures is not reached
-        root.signed.roles["snapshot"].threshold = 2
+        root.signed.roles[RoleNames.SNAPSHOT.value].threshold = 2
         with self.assertRaises(exceptions.UnsignedMetadataError):
-            root.verify_delegate("snapshot", snapshot)
+            root.verify_delegate(RoleNames.SNAPSHOT.value, snapshot)
 
         # verify succeeds when we correct the new signature and reach the
         # threshold of 2 keys
-        snapshot.sign(SSlibSigner(self.keystore["timestamp"]), append=True)
-        root.verify_delegate("snapshot", snapshot)
+        snapshot.sign(SSlibSigner(self.keystore[RoleNames.TIMESTAMP.value]), append=True)
+        root.verify_delegate(RoleNames.SNAPSHOT.value, snapshot)
 
     def test_key_class(self):
         # Test if from_securesystemslib_key removes the private key from keyval
@@ -433,44 +434,44 @@ def test_root_add_key_and_remove_key(self):
         )
 
         # Assert that root does not contain the new key
-        self.assertNotIn(keyid, root.signed.roles["root"].keyids)
+        self.assertNotIn(keyid, root.signed.roles[RoleNames.ROOT.value].keyids)
         self.assertNotIn(keyid, root.signed.keys)
 
         # Add new root key
-        root.signed.add_key("root", key_metadata)
+        root.signed.add_key(RoleNames.ROOT.value, key_metadata)
 
         # Assert that key is added
-        self.assertIn(keyid, root.signed.roles["root"].keyids)
+        self.assertIn(keyid, root.signed.roles[RoleNames.ROOT.value].keyids)
         self.assertIn(keyid, root.signed.keys)
 
         # Confirm that the newly added key does not break
         # the object serialization
         root.to_dict()
 
         # Try adding the same key again and assert its ignored.
-        pre_add_keyid = root.signed.roles["root"].keyids.copy()
-        root.signed.add_key("root", key_metadata)
-        self.assertEqual(pre_add_keyid, root.signed.roles["root"].keyids)
+        pre_add_keyid = root.signed.roles[RoleNames.ROOT.value].keyids.copy()
+        root.signed.add_key(RoleNames.ROOT.value, key_metadata)
+        self.assertEqual(pre_add_keyid, root.signed.roles[RoleNames.ROOT.value].keyids)
 
         # Add the same key to targets role as well
-        root.signed.add_key("targets", key_metadata)
+        root.signed.add_key(RoleNames.TARGETS.value, key_metadata)
 
         # Add the same key to a nonexistent role.
         with self.assertRaises(ValueError):
             root.signed.add_key("nosuchrole", key_metadata)
 
         # Remove the key from root role (targets role still uses it)
-        root.signed.remove_key("root", keyid)
-        self.assertNotIn(keyid, root.signed.roles["root"].keyids)
+        root.signed.remove_key(RoleNames.ROOT.value, keyid)
+        self.assertNotIn(keyid, root.signed.roles[RoleNames.ROOT.value].keyids)
         self.assertIn(keyid, root.signed.keys)
 
         # Remove the key from targets as well
-        root.signed.remove_key("targets", keyid)
-        self.assertNotIn(keyid, root.signed.roles["targets"].keyids)
+        root.signed.remove_key(RoleNames.TARGETS.value, keyid)
+        self.assertNotIn(keyid, root.signed.roles[RoleNames.TARGETS.value].keyids)
         self.assertNotIn(keyid, root.signed.keys)
 
         with self.assertRaises(ValueError):
-            root.signed.remove_key("root", "nosuchkey")
+            root.signed.remove_key(RoleNames.ROOT.value, "nosuchkey")
         with self.assertRaises(ValueError):
             root.signed.remove_key("nosuchrole", keyid)
 
@@ -661,7 +662,7 @@ def test_length_and_hash_validation(self):
         targets_path = os.path.join(self.repo_dir, "metadata", "targets.json")
         targets = Metadata[Targets].from_file(targets_path)
         file1_targetfile = targets.signed.targets["file1.txt"]
-        filepath = os.path.join(self.repo_dir, "targets", "file1.txt")
+        filepath = os.path.join(self.repo_dir, RoleNames.TARGETS.value, "file1.txt")
 
         with open(filepath, "rb") as file1:
             file1_targetfile.verify_length_and_hashes(file1)
@@ -679,7 +680,7 @@ def test_length_and_hash_validation(self):
 
     def test_targetfile_from_file(self):
         # Test with an existing file and valid hash algorithm
-        file_path = os.path.join(self.repo_dir, "targets", "file1.txt")
+        file_path = os.path.join(self.repo_dir, RoleNames.TARGETS.value, "file1.txt")
         targetfile_from_file = TargetFile.from_file(
             file_path, file_path, ["sha256"]
         )
@@ -688,20 +689,20 @@ def test_targetfile_from_file(self):
             targetfile_from_file.verify_length_and_hashes(file)
 
         # Test with a non-existing file
-        file_path = os.path.join(self.repo_dir, "targets", "file123.txt")
+        file_path = os.path.join(self.repo_dir, RoleNames.TARGETS.value, "file123.txt")
         with self.assertRaises(FileNotFoundError):
             TargetFile.from_file(
                 file_path, file_path, [sslib_hash.DEFAULT_HASH_ALGORITHM]
             )
 
         # Test with an unsupported algorithm
-        file_path = os.path.join(self.repo_dir, "targets", "file1.txt")
+        file_path = os.path.join(self.repo_dir, RoleNames.TARGETS.value, "file1.txt")
         with self.assertRaises(exceptions.UnsupportedAlgorithmError):
             TargetFile.from_file(file_path, file_path, ["123"])
 
     def test_targetfile_from_data(self):
         data = b"Inline test content"
-        target_file_path = os.path.join(self.repo_dir, "targets", "file1.txt")
+        target_file_path = os.path.join(self.repo_dir, RoleNames.TARGETS.value, "file1.txt")
 
         # Test with a valid hash algorithm
         targetfile_from_data = TargetFile.from_data(