Invalid conversion from runtime type String to Integer

Generated test classes fails with below error.

Error:
"System.TypeException: Invalid conversion from runtime type String to Integer"

Api where failure happens: -> 'propertyId' => (Integer) params.get('id')

public Attributes getAttributes(Map<String, Object> params) {
    client.assertNotNull(params.get('id'), 'propertyId');
    List<OAS.Param> query = new List<OAS.Param>();
    List<OAS.Param> form = new List<OAS.Param>();

    return (Attributes) client.invoke(
        'GET', '/{id}/attributes', '',
        query, form,
        new Map<String, Object>{
            'propertyId' => (Integer) params.get('id')
        },

Api test where failure happens:
Map<String, Object> params = new Map<String, Object>{
'id' => ''
};

Doc:
"parameters": [
{
"name": "id",
"in": "path",
"description": "The unique identifier.",
"required": true,
"schema": {
"type": "integer",
"format": "int32"
}
}
],

Start from the generated getAttributes method and its corresponding generated API test, then compare the OpenAPI path parameter schema with the value placed in params. Reproduce the String-to-Integer failure and identify the generator entry point responsible for this parameter conversion. Done means the generated test no longer raises the reported TypeException for the documented integer parameter.