Packages

  • package root
    Definition Classes
    root
  • package org
    Definition Classes
    root
  • package scalatest

    ScalaTest's main traits, classes, and other members, including members supporting ScalaTest's DSL for the Scala interpreter.

    ScalaTest's main traits, classes, and other members, including members supporting ScalaTest's DSL for the Scala interpreter.

    Definition Classes
    org
  • trait PrivateMethodTester extends AnyRef

    Trait that facilitates the testing of private methods.

    Trait that facilitates the testing of private methods.

    To test a private method, mix in trait PrivateMethodTester and create a PrivateMethod object, like this:

    val decorateToStringValue = PrivateMethod[String]('decorateToStringValue)

    The type parameter on PrivateMethod, in this case String, is the result type of the private method you wish to invoke. The symbol passed to the PrivateMethod.apply factory method, in this case 'decorateToStringValue, is the name of the private method to invoke. To test the private method, use the invokePrivate operator, like this:

    targetObject invokePrivate decorateToStringValue(1)

    Here, targetObject is a variable or singleton object name referring to the object whose private method you want to test. You pass the arguments to the private method in the parentheses after the PrivateMethod object. The result type of an invokePrivate operation will be the type parameter of the PrivateMethod object, thus you need not cast the result to use it. In other words, after creating a PrivateMethod object, the syntax to invoke the private method looks like a regular method invocation, but with the dot (.) replaced by invokePrivate. The private method is invoked dynamically via reflection, so if you have a typo in the method name symbol, specify the wrong result type, or pass invalid parameters, the invokePrivate operation will compile, but throw an exception at runtime.

    One limitation to be aware of is that you can't use PrivateMethodTester to test a private method declared in a trait, because the class the trait gets mixed into will not declare that private method. Only the class generated to hold method implementations for the trait will have that private method. If you want to test a private method declared in a trait, and that method does not use any state of that trait, you can move the private method to a companion object for the trait and test it using PrivateMethodTester that way. If the private trait method you want to test uses the trait's state, your best options are to test it indirectly via a non-private trait method that calls the private method, or make the private method package access and test it directly via regular static method invocations.

    Also, if you want to use PrivateMethodTester to invoke a parameterless private method, you'll need to use empty parens. Instead of:

    targetObject invokePrivate privateParameterlessMethod

    You'll need to write:

    targetObject invokePrivate privateParameterlessMethod()

    Definition Classes
    scalatest
  • Invocation
  • Invoker
  • PrivateMethod

final class Invoker extends AnyRef

Class used via an implicit conversion to enable private methods to be tested.

Source
PrivateMethodTester.scala
Linear Supertypes
AnyRef, Any
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Inherited
  1. Invoker
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Visibility
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Instance Constructors

  1. new Invoker(target: AnyRef)

Value Members

  1. def invokePrivate[T](invocation: Invocation[T]): T

    Invoke a private method.

    Invoke a private method. This method will attempt to invoke via reflection a private method. The name of the method to invoke is contained in the methodName field of the passed Invocation. The arguments to pass are contained in the args field. The object on which to invoke the private method is the target object passed to this Invoker's primary constructor. The type parameter, T, is the return type of the private method.

    invocation

    the Invocation object containing the method name symbol and args of the invocation.

    returns

    the value returned by the invoked private method

    Exceptions thrown

    IllegalArgumentException if the target object does not have a method of the name, with argument types compatible with the objects in the passed args array, specified in the passed Invocation object.