org.scalatest.exceptions.ModifiablePayload.scala Maven / Gradle / Ivy
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/*
* Copyright 2001-2012 Artima, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.scalatest.exceptions
/**
* Trait implemented by PayloadField exception types that can modify their payload.
*
*
* This trait facilitates the withPayload construct provided by trait
* Payloads. This construct enables a payload object (or modified
* payload object) to be included as the payload of a thrown exception. The payload
* can then be included in the ScalaTest event that results from that exception. For
* example, the payload included in a TestFailedException will be included
* as the payload of the resulting TestFailed event. Here's an example in
* which a GUI snapshot is included as a payload when a test fails:
*
*
*
* withPayload(generateGUISnapshot()) {
* 1 + 1 should be === 3
* }
*
*
*
* Exception types that mix in this trait have a modifyPayload method, which
* returns an exception identical to itself, except with the payload option replaced with
* the result of invoking the passed function, supplying the current payload option
* as the lone Option[Any] parameter.
*
*/
trait ModifiablePayload[T <: Throwable] { this: Throwable with PayloadField =>
/**
* Returns an instance of this exception's class, identical to this exception,
* except with the payload option replaced with
* the result of invoking the passed function, fun, supplying the current payload option
* as the lone Option[Any] parameter.
*
*
* Implementations of this method may either mutate this exception or return
* a new instance with the revised detail message.
*
*
* @param fun A function that returns the new payload option given the old one
*/
def modifyPayload(fun: Option[Any] => Option[Any]): T
}