The update_function_configuration currently returns an empty dict no matter what but certain lambda libraries (ie, Zappa) require a realistic return value... which is simply the current config after being updated.

https://github.com/localstack/localstack/blob/9cba1010dfcbf2b7672df4d7da46b7e8ab287f64/localstack/services/awslambda/lambda_api.py#L872

https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/lambda.html#Lambda.Client.update_function_configuration

There might also be some other magic enriching that result but my quick read-through looks like it's an empty dict.



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runtime=LAMBDA_RUNTIME_PYTHON36
        )
        testutil.create_lambda_function(
            func_name=TEST_LAMBDA_NAME_PY3,
            zip_file=zip_file,
            runtime=LAMBDA_RUNTIME_PYTHON36
        )
        result = self.lambda_client.invoke(
            FunctionName=TEST_LAMBDA_NAME_PY3, Payload=b'{}')
        result_data = result['Payload'].read()
        self.assertEqual(result['StatusCode'], 200)
        self.assertEqual(to_str(result_data).strip(), '{}')
        
        testutil.delete_lambda_function(TEST_LAMBDA_NAME_PY3)
    def test_handler_in_submodule(self):
        func_name = 'lambda-%s' % short_uid()
        zip_file = testutil.create_lambda_archive(
            load_file(TEST_LAMBDA_PYTHON), get_content=True,
            libs=TEST_LAMBDA_LIBS, runtime=LAMBDA_RUNTIME_PYTHON36,
            file_name='abc/def/main.py')
        testutil.create_lambda_function(func_name=func_name, zip_file=zip_file,
            handler='abc.def.main.handler', runtime=LAMBDA_RUNTIME_PYTHON36)
        
        result = self.lambda_client.invoke(FunctionName=func_name, Payload=b'{}')
        result_data = json.loads(result['Payload'].read())
        self.assertEqual(result['StatusCode'], 200)
        self.assertEqual(result_data['event'], json.loads('{}'))
class TestNodeJSRuntimes(LambdaTestBase):
    @classmethod
    def setUpClass(cls):