{
    "description": "Request has a negative banner format width minimum.",
    "mockBidRequest": {
        "id": "req-id",
        "imp": [{
            "id": "imp-id",
            "banner": {
                "format": [{
                    "w": 50,
                    "h": 50,
                    "wmin": -1
                }]
            }
        }],
        "app": {
            "id": "app_001"
        }
    },
    "expectedReturnCode": 400,
    "expectedErrorMessage": "Invalid request: request.imp[0].banner.format[0].wmin must be a positive number"
}