Test new API: serialization tests for invalid arg

A while ago we decided that it's best to research each of the individuals
attributes one by one and identify what level of validation it needs
compared to how we use it:
#1366 (comment).

This work is ongoing and there are a couple of commits already merged
for this:
- 6c5d970
- f20664d
- 41afb1e

We want to be able to test the attributes validation against known bad
values.
The way we want to do that is with table testing we have added
using decorators for our metadata classes defined in New API:
#1416.
This gives us an easy way to add new cases for each of the attributes and
not depend on external files.

Signed-off-by: Martin Vrachev <[email protected]>

Author: MVrachev

tests/test_metadata_serialization.py

@@ -12,11 +12,13 @@
 import unittest
 import copy
 
-from typing import Dict, Callable
+from typing import Dict, Callable, Optional, Mapping, Any
+from datetime import datetime
 
 from tests import utils
 
 from tuf.api.metadata import (
+    Signed,
     Root,
     Snapshot,
     Timestamp,
@@ -50,6 +52,44 @@ def wrapper(test_cls: "TestSerialization"):
 
 class TestSerialization(unittest.TestCase):
 
+    # Snapshot instances with meta = {} are valid, but for a full valid
+    # repository it's required that meta has at least one element inside it.
+    invalid_signed: DataSet = {
+        "no _type": '{"spec_version": "1.0.0", "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "no spec_version": '{"_type": "signed", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "no version": '{"_type": "signed", "spec_version": "1.0.0", "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "no expires": '{"_type": "signed", "spec_version": "1.0.0", "version": 1, "meta": {}}',
+        "empty str _type":
+            '{"_type": "", "spec_version": "1.0.0", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "empty str spec_version":
+            '{"_type": "signed", "spec_version": "", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "_type wrong type":
+            '{"_type": "foo", "spec_version": "1.0.0", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "version wrong type":
+            '{"_type": "signed", "spec_version": "1.0.0", "version": "a", "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "invalid spec_version str":
+            '{"_type": "signed", "spec_version": "abc", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "two digit spec_version":
+            '{"_type": "signed", "spec_version": "1.2.a", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "no digit spec_version":
+            '{"_type": "signed", "spec_version": "a.b.c", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "different major spec_version":
+            '{"_type": "signed", "spec_version": "0.0.0", "version": 1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "version 0":
+            '{"_type": "signed", "spec_version": "1.0.0", "version": 0, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "version below 0":
+            '{"_type": "signed", "spec_version": "1.0.0", "version": -1, "expires": "2030-01-01T00:00:00Z", "meta": {}}',
+        "wrong datetime string":
+            '{"_type": "signed", "spec_version": "1.0.0", "version": 1, "expires": "abc", "meta": {}}',
+    }
+
+    @run_sub_tests_with_dataset(invalid_signed)
+    def test_invalid_signed_serialization(self, test_case_data: Dict[str, str]):
+        case_dict = json.loads(test_case_data)
+        with self.assertRaises((KeyError, ValueError, TypeError)):
+            Snapshot.from_dict(copy.deepcopy(case_dict))
+
+
     valid_keys: DataSet = {
         "all": '{"keytype": "rsa", "scheme": "rsassa-pss-sha256", \
             "keyval": {"public": "foo"}}',
@@ -60,12 +100,45 @@ class TestSerialization(unittest.TestCase):
     }
 
     @run_sub_tests_with_dataset(valid_keys)
-    def test_key_serialization(self, test_case_data: str):
+    def test_valid_key_serialization(self, test_case_data: str):
         case_dict = json.loads(test_case_data)
         key = Key.from_dict("id", copy.copy(case_dict))
         self.assertDictEqual(case_dict, key.to_dict())
 
 
+    invalid_keys: DataSet = {
+        "no keyid": '{"keytype": "rsa", "scheme": "rsassa-pss-sha256", "keyval": {"public": "abc"}}',
+        "no keytype": '{"keyid": "id", "scheme": "rsassa-pss-sha256", "keyval": {"public": "foo"}}',
+        "no scheme": '{"keyid": "id", "keytype": "rsa", "keyval": {"public": "foo"}}',
+        "no keyval": '{"keyid": "id", "keytype": "rsa", "scheme": "rsassa-pss-sha256"}',
+        "keyid wrong type": '{"keyid": 1, "keytype": "rsa", "scheme": "rsassa-pss-sha256", "keyval": {"public": "abc"}}',
+        "keytype wrong type": '{"keyid": "id", "keytype": 1, "scheme": "rsassa-pss-sha256", "keyval": {"public": "abc"}}',
+        "scheme wrong type": '{"keyid": "id", "keytype": "rsa", "scheme": 1, "keyval": {"public": "abc"}}',
+        "keyval wrong type": '{"keyid": "id", "keytype": "rsa", "scheme": "rsassa-pss-sha256", "keyval": 1}',
+    }
+
+    @run_sub_tests_with_dataset(invalid_keys)
+    def test_invalid_key_serialization(self, test_case_data: Dict[str, str]):
+        case_dict = json.loads(test_case_data)
+        with self.assertRaises((TypeError, KeyError)):
+            keyid = case_dict.pop("keyid")
+            Key.from_dict(keyid, copy.copy(case_dict))
+
+    invalid_roles: DataSet = {
+        "no threshold": '{"keyids": ["keyid"]}',
+        "no keyids": '{"threshold": 3}',
+        "wrong threshold type": '{"keyids": ["keyid"], "threshold": "a"}',
+        "threshold below 1": '{"keyids": ["keyid"], "threshold": 0}',
+        "duplicate keyids": '{"keyids": ["keyid", "keyid"], "threshold": 3}',
+    }
+
+    @run_sub_tests_with_dataset(invalid_roles)
+    def test_invalid_role_serialization(self, test_case_data: Dict[str, str]):
+        case_dict = json.loads(test_case_data)
+        with self.assertRaises((KeyError, TypeError, ValueError)):
+            Role.from_dict(copy.deepcopy(case_dict))
+
+
     valid_roles: DataSet = {
         "all": '{"keyids": ["keyid"], "threshold": 3}',
         "unrecognized field": '{"keyids": ["keyid"], "threshold": 3, "foo": "bar"}',
@@ -102,12 +175,28 @@ def test_root_serialization(self, test_case_data: str):
         root = Root.from_dict(copy.deepcopy(case_dict))
         self.assertDictEqual(case_dict, root.to_dict())
 
+
+    invalid_metafiles: DataSet = {
+        "wrong length type": '{"version": 1, "length": "a", "hashes": {"sha256" : "abc"}}',
+        "length 0": '{"version": 1, "length": 0, "hashes": {"sha256" : "abc"}}',
+        "length below 0": '{"version": 1, "length": -1, "hashes": {"sha256" : "abc"}}',
+        "empty hashes dict": '{"version": 1, "length": 1, "hashes": {}}',
+        "hashes wrong type": '{"version": 1, "length": 1, "hashes": 1}',
+        "hashes values wrong type": '{"version": 1, "length": 1, "hashes": {"sha256": 1}}',
+    }
+
+    @run_sub_tests_with_dataset(invalid_metafiles)
+    def test_invalid_metafile_serialization(self, test_case_data: Dict[str, str]):
+        case_dict = json.loads(test_case_data)
+        with self.assertRaises((TypeError, ValueError, AttributeError)):
+            MetaFile.from_dict(copy.deepcopy(case_dict))
+
+
     valid_metafiles: DataSet = {
         "all": '{"hashes": {"sha256" : "abc"}, "length": 12, "version": 1}',
         "no length": '{"hashes": {"sha256" : "abc"}, "version": 1 }',
         "no hashes": '{"length": 12, "version": 1}',
-        "unrecognized field": '{"hashes": {"sha256" : "abc"}, "length": 12, "version": 1, \
-            "foo": "bar"}',
+        "unrecognized field": '{"hashes": {"sha256" : "abc"}, "length": 12, "version": 1, "foo": "bar"}',
     }
 
     @run_sub_tests_with_dataset(valid_metafiles)
@@ -181,6 +270,20 @@ def test_delegation_serialization(self, test_case_data: str):
         self.assertDictEqual(case_dict, delegation.to_dict())
 
 
+    invalid_targetfiles: DataSet = {
+        "no hashes": '{"length": 1}',
+        "no length": '{"hashes": {"sha256": "abc"}}'
+        # The remaining cases are the same as for invalid_hashes and
+        # invalid_length datasets.
+    }
+
+    @run_sub_tests_with_dataset(invalid_targetfiles)
+    def test_invalid_targetfile_serialization(self, test_case_data: Dict[str, str]):
+        case_dict = json.loads(test_case_data)
+        with self.assertRaises(KeyError):
+            TargetFile.from_dict(copy.deepcopy(case_dict))
+
+
     valid_targetfiles: DataSet = {
         "all": '{"length": 12, "hashes": {"sha256" : "abc"}, \
             "custom" : {"foo": "bar"} }',