Array-typed query parameters do not seem to assume "collectionFormat": "csv" by default...

[johanste]

Using

node_modules/.bin/autorest --use=@autorest/python@5.1.0-preview.3

The following swagger:

{
    "swagger": "2.0",
    "info": {
        "title": "Bug?",
        "version": "1.0"
    },
    "paths": {
        "/thing": {
            "get": {
                "operationId": "whoCares",
                "parameters": [
                    {
                        "name": "param",
                        "in": "query",
                        "type": "array",
                        "items": {
                            "type": "string"
                        }
                    }
                ],
                "responses": {
                    "200": {
                        "description": "Ok"
                    }
                }
            }
        }
    }
}

generates the following query parameter serialization code:

        # Construct parameters
        query_parameters = {}  # type: Dict[str, Any]
        if param is not None:
            query_parameters['param'] = self._serialize.query("param", param, '[str]')

It is missing the div=',' parameter to the self._serialize.query(...)` call...

[iscai-msft]

Determined that m4 should fix this. Here are the issues filed for this issue:
Azure/perks#117
https://github.com/Azure/autorest.modelerfour/issues/314