Fix botocore regional client use to avoid issues in #124 (#125)

* add extra itertools-like permuter helpers

* add permuted valid arguments test for AwsKmsCryptographicMaterialsProvider

* fix AwsKmsCryptographicMaterialsProvider.__attrs_post_init__ value override

fixes #124

* update changelog with #124 fix

* specify region_name in test value

CHANGELOG.rst

@@ -2,6 +2,14 @@
 Changelog
 *********
 
+1.1.2 -- 2019-09-??
+===================
+
+Bugfixes
+--------
+* Fix :class:`AwsKmsCryptographicMaterialsProvider` regional clients override bug
+  `#124 <https://github.com/aws/aws-dynamodb-encryption-python/issues/124>`_
+
 1.1.1 -- 2019-08-29
 ===================
 

src/dynamodb_encryption_sdk/material_providers/aws_kms.py

@@ -214,9 +214,6 @@ def __attrs_post_init__(self):
             default_algorithm=_DEFAULT_SIGNING_ALGORITHM,
             default_key_length=_DEFAULT_SIGNING_KEY_LENGTH,
         )
-        self._regional_clients = (
-            {}
-        )  # type: Dict[Text, botocore.client.BaseClient]  # noqa pylint: disable=attribute-defined-outside-init
 
     def _add_regional_client(self, region_name):
         # type: (Text) -> None

test/unit/material_providers/test_aws_kms.py

@@ -32,6 +32,8 @@
 )
 from dynamodb_encryption_sdk.structures import EncryptionContext
 
+from ..unit_test_utils import all_possible_combinations_kwargs
+
 pytestmark = [pytest.mark.unit, pytest.mark.local]
 
 _VALID_KEY_INFO_KWARGS = dict(description="some string", algorithm="algorithm name", length=1234)
@@ -218,6 +220,38 @@ def test_loaded_key_infos():
     assert cmp._regional_clients == {}
 
 
+@pytest.mark.parametrize(
+    "kwargs",
+    [
+        pytest.param(val, id=str(val))
+        for val in all_possible_combinations_kwargs(
+            dict(),
+            dict(botocore_session=botocore.session.Session()),
+            dict(grant_tokens=("sdvoaweih", "auwshefiouawh")),
+            dict(material_description={"asoiufeoia": "soajfijewi"}),
+            dict(
+                regional_clients={
+                    "my-region-1": boto3.session.Session().client(
+                        "kms", region_name="not-a-real-region", endpoint_url="https://not-a-real-url"
+                    )
+                }
+            ),
+        )
+    ],
+)
+def test_kms_cmp_values_set(kwargs):
+    cmp = AwsKmsCryptographicMaterialsProvider(key_id="example_key_id", **kwargs)
+
+    assert cmp._key_id == "example_key_id"
+
+    if "botocore_session" in kwargs:
+        assert cmp._botocore_session == kwargs["botocore_session"]
+
+    assert cmp._grant_tokens == kwargs.get("grant_tokens", ())
+    assert cmp._material_description == kwargs.get("material_description", {})
+    assert cmp._regional_clients == kwargs.get("regional_clients", {})
+
+
 def test_add_regional_client_known_region(default_kms_cmp, patch_boto3_session):
     default_kms_cmp._regional_clients[sentinel.region] = sentinel.client
 

test/unit/unit_test_utils.py

@@ -11,6 +11,8 @@
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 """Helper utilities for unit tests."""
+import itertools
+
 import pytest
 
 from dynamodb_encryption_sdk.delegated_keys.jce import JceNameLocalDelegatedKey
@@ -25,3 +27,16 @@ def wrapped_cmp():
         signing_key=signing_key, wrapping_key=wrapping_key, unwrapping_key=wrapping_key
     )
     return cmp
+
+
+def all_possible_combinations(*base_values):
+    combinations = [itertools.combinations(base_values, i) for i in range(1, len(base_values) + 1)]
+    return itertools.chain(*combinations)
+
+
+def all_possible_combinations_kwargs(*base_values):
+    for combo in all_possible_combinations(*base_values):
+        kwargs = {}
+        for values in combo:
+            kwargs.update(values)
+        yield kwargs