{
    "description": "Request has a negative banner width.",
    "mockBidRequest": {
        "id": "req-id",
        "site": {
            "id": "some-site"
        },
        "imp": [{
            "id": "imp-id",
            "banner": {
                "w": -1,
                "h": 50
            },
            "ext": {
                "appnexus": {
                    "placementId": 12883451
                }
            }
        }]
    },
    "expectedReturnCode": 400,
    "expectedErrorMessage": "Invalid request: request.imp[0].banner.w must be a positive number"
}