如何为Play Framework JSON阅读器编写单元测试

Question

我希望为shipmentNumberValidator方法编写单元测试，其中Reads是play.api.libs.json.Reads。我该怎么做？

object Validator { 
    def shipmentNumberValidator(): Reads[String] = 
     Reads.filter(ValidationError(ErrorConstants.BAD_SHIPMENT_NUMBER))(_.matches(BarcodePatterns.ShipmentNumber)) 
} 

单元测试应该传递给它一个装运编号，并且该方法返回任一成功装运数或错误消息，如果装运编号格式不匹配。我不知道如何将值传递给此方法。

的方法通常是在配套使用的对象隐读，如：

object ShipmentOrder { 
    implicit val shipmentOrderReads: Reads[ShipmentOrder] = (
    (JsPath \ "id").read[String](Validator.missingFieldValidator("id") keepAnd Validator.shipmentNumberValidator())(ShipmentOrder.apply _) 
} 

Answer 1

根据test framework您使用（如specs2），你可以测试预期如下：

• 做一个Json.parse("{expectedJson}") must be JsResult(expectedInstance)
• 做一个Json.parse("{unexpectedJson}") must be JsError(_)

使用规格2：

import play.api.libs.json._ 

"JSON" should { 
    "be successfully parsed when expected" in { 
    Json.parse("""{"expected":"json"}""") must beLike[JsResult[ShipmentOrder]] { 
     case JsSuccess(parsed, _) => 
     parsed must_== expectedShipmentOrder 
    } 
    } 

    "fail to be parsed if expected" in { 
    Json.parse("""{"unexpected":"json"}""") must beLike[JsResult[ShipmentOrder]] { 
     case JsError(details) => 
     ok // possible check `details` 
    } 
    } 
}