diff --git a/tests/test_api.py b/tests/test_api.py
index 00733132e9..7bdaf3ae3b 100755
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -13,6 +13,7 @@
 import shutil
 import tempfile
 import unittest
+import copy
 
 from datetime import datetime, timedelta
 from dateutil.relativedelta import relativedelta
@@ -42,6 +43,10 @@ def setUpModule():
         import_ed25519_privatekey_from_file
     )
 
+    from securesystemslib.keys import (
+        format_keyval_to_metadata
+    )
+
 logger = logging.getLogger(__name__)
 
 
@@ -215,12 +220,14 @@ def test_metadata_snapshot(self):
         snapshot = Metadata.from_json_file(snapshot_path)
 
         # Create a dict representing what we expect the updated data to be
-        fileinfo = snapshot.signed.meta
+        fileinfo = copy.deepcopy(snapshot.signed.meta)
         hashes = {'sha256': 'c2986576f5fdfd43944e2b19e775453b96748ec4fe2638a6d2f32f1310967095'}
         fileinfo['role1.json']['version'] = 2
         fileinfo['role1.json']['hashes'] = hashes
         fileinfo['role1.json']['length'] = 123
 
+
+        self.assertNotEqual(snapshot.signed.meta, fileinfo)
         snapshot.signed.update('role1', 2, 123, hashes)
         self.assertEqual(snapshot.signed.meta, fileinfo)
 
@@ -250,14 +257,73 @@ def test_metadata_timestamp(self):
         self.assertEqual(timestamp.signed.expires, datetime(2036, 1, 3, 0, 0))
 
         hashes = {'sha256': '0ae9664468150a9aa1e7f11feecb32341658eb84292851367fea2da88e8a58dc'}
-        fileinfo = timestamp.signed.meta['snapshot.json']
+        fileinfo = copy.deepcopy(timestamp.signed.meta['snapshot.json'])
         fileinfo['hashes'] = hashes
         fileinfo['version'] = 2
         fileinfo['length'] = 520
+
+        self.assertNotEqual(timestamp.signed.meta['snapshot.json'], fileinfo)
         timestamp.signed.update(2, 520, hashes)
         self.assertEqual(timestamp.signed.meta['snapshot.json'], fileinfo)
 
 
+    def test_metadata_root(self):
+        root_path = os.path.join(
+                self.repo_dir, 'metadata', 'root.json')
+        root = Metadata.from_json_file(root_path)
+
+        # Add a second key to root role
+        root_key2 =  import_ed25519_publickey_from_file(
+                    os.path.join(self.keystore_dir, 'root_key2.pub'))
+
+        keyid = root_key2['keyid']
+        key_metadata = format_keyval_to_metadata(
+            root_key2['keytype'], root_key2['scheme'], root_key2['keyval'])
+
+        # Assert that root does not contain the new key
+        self.assertNotIn(keyid, root.signed.roles['root']['keyids'])
+        self.assertNotIn(keyid, root.signed.keys)
+
+        # Add new root key
+        root.signed.add_key('root', keyid, key_metadata)
+
+        # Assert that key is added
+        self.assertIn(keyid, root.signed.roles['root']['keyids'])
+        self.assertIn(keyid, root.signed.keys)
+
+        # Remove the key
+        root.signed.remove_key('root', keyid)
+
+        # Assert that root does not contain the new key anymore
+        self.assertNotIn(keyid, root.signed.roles['root']['keyids'])
+        self.assertNotIn(keyid, root.signed.keys)
+
+
+
+    def test_metadata_targets(self):
+        targets_path = os.path.join(
+                self.repo_dir, 'metadata', 'targets.json')
+        targets = Metadata.from_json_file(targets_path)
+
+        # Create a fileinfo dict representing what we expect the updated data to be
+        filename = 'file2.txt'
+        hashes = {
+            "sha256": "141f740f53781d1ca54b8a50af22cbf74e44c21a998fa2a8a05aaac2c002886b",
+            "sha512": "ef5beafa16041bcdd2937140afebd485296cd54f7348ecd5a4d035c09759608de467a7ac0eb58753d0242df873c305e8bffad2454aa48f44480f15efae1cacd0"
+        },
+
+        fileinfo = {
+            'hashes': hashes,
+            'length': 28
+        }
+
+        # Assert that data is not aleady equal
+        self.assertNotEqual(targets.signed.targets[filename], fileinfo)
+        # Update an already existing fileinfo
+        targets.signed.update(filename, fileinfo)
+        # Verify that data is updated
+        self.assertEqual(targets.signed.targets[filename], fileinfo)
+
 # Run unit test.
 if __name__ == '__main__':
     utils.configure_test_logging(sys.argv)
diff --git a/tuf/api/metadata.py b/tuf/api/metadata.py
index 0b1ee08284..a747be6d13 100644
--- a/tuf/api/metadata.py
+++ b/tuf/api/metadata.py
@@ -88,8 +88,7 @@ class also that has a 'from_dict' factory method. (Currently this is
         elif _type == 'timestamp':
             inner_cls = Timestamp
         elif _type == 'root':
-            # TODO: implement Root class
-            raise NotImplementedError('Root not yet implemented')
+            inner_cls = Root
         else:
             raise ValueError(f'unrecognized metadata type "{_type}"')
 
@@ -335,6 +334,89 @@ def bump_version(self) -> None:
         self.version += 1
 
 
+class Root(Signed):
+    """A container for the signed part of root metadata.
+
+    Attributes:
+        consistent_snapshot: A boolean indicating whether the repository
+            supports consistent snapshots.
+        keys: A dictionary that contains a public key store used to verify
+            top level roles metadata signatures::
+            {
+                '<KEYID>': {
+                    'keytype': '<KEY TYPE>',
+                    'scheme': '<KEY SCHEME>',
+                    'keyid_hash_algorithms': [
+                        '<HASH ALGO 1>',
+                        '<HASH ALGO 2>'
+                        ...
+                    ],
+                    'keyval': {
+                        'public': '<PUBLIC KEY HEX REPRESENTATION>'
+                    }
+                },
+                ...
+            },
+        roles: A dictionary that contains a list of signing keyids and
+            a signature threshold for each top level role::
+            {
+                '<ROLE>': {
+                    'keyids': ['<SIGNING KEY KEYID>', ...],
+                    'threshold': <SIGNATURE THRESHOLD>,
+                },
+                ...
+            }
+
+    """
+    # TODO: determine an appropriate value for max-args and fix places where
+    # we violate that. This __init__ function takes 7 arguments, whereas the
+    # default max-args value for pylint is 5
+    # pylint: disable=too-many-arguments
+    def __init__(
+            self, _type: str, version: int, spec_version: str,
+            expires: datetime, consistent_snapshot: bool,
+            keys: JsonDict, roles: JsonDict) -> None:
+        super().__init__(_type, version, spec_version, expires)
+        # TODO: Add classes for keys and roles
+        self.consistent_snapshot = consistent_snapshot
+        self.keys = keys
+        self.roles = roles
+
+
+    # Serialization.
+    def to_dict(self) -> JsonDict:
+        """Returns the JSON-serializable dictionary representation of self. """
+        json_dict = super().to_dict()
+        json_dict.update({
+            'consistent_snapshot': self.consistent_snapshot,
+            'keys': self.keys,
+            'roles': self.roles
+        })
+        return json_dict
+
+
+    # Update key for a role.
+    def add_key(self, role: str, keyid: str, key_metadata: JsonDict) -> None:
+        """Adds new key for 'role' and updates the key store. """
+        if keyid not in self.roles[role]['keyids']:
+            self.roles[role]['keyids'].append(keyid)
+            self.keys[keyid] = key_metadata
+
+
+    # Remove key for a role.
+    def remove_key(self, role: str, keyid: str) -> None:
+        """Removes key for 'role' and updates the key store. """
+        if keyid in self.roles[role]['keyids']:
+            self.roles[role]['keyids'].remove(keyid)
+            for keyinfo in self.roles.values():
+                if keyid in keyinfo['keyids']:
+                    return
+
+            del self.keys[keyid]
+
+
+
+
 class Timestamp(Signed):
     """A container for the signed part of timestamp metadata.