fix: check if self._kwargs is None before using it

Author: matthiasschaub

core/testcontainers/core/container.py

@@ -216,7 +216,7 @@ def start(self) -> Self:
                 self.ports,
                 self._name,
                 self.volumes,
-                str(tuple(sorted(self._kwargs.values()))),
+                str(tuple(sorted(self._kwargs.values()))) if self._kwargs else None,
             ]
             hash_ = str(zlib.crc32(pickle.dumps(args)))
             docker_client = self.get_docker_client()

core/tests/test_reusable_containers.py

@@ -114,7 +114,7 @@ def test_docker_container_labels_hash_default():
 def test_docker_container_labels_hash(monkeypatch):
     tc_properties_mock = testcontainers_config.tc_properties | {"testcontainers.reuse.enable": "true"}
     monkeypatch.setattr(testcontainers_config, "tc_properties", tc_properties_mock)
-    expected_hash = "1296172062"
+    expected_hash = "380705419"
     with DockerContainer("hello-world").with_reuse() as container:
         assert container._container is not None
         assert container._container.labels["hash"] == expected_hash