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 EitherValues extends AnyRef

    Trait that provides an implicit conversion that adds left.value and right.value methods to Either, which will return the selected value of the Either if defined, or throw TestFailedException if not.

    Trait that provides an implicit conversion that adds left.value and right.value methods to Either, which will return the selected value of the Either if defined, or throw TestFailedException if not.

    This construct allows you to express in one statement that an Either should be left or right and that its value should meet some expectation. Here's are some examples:

    either1.right.value should be > 9
either2.left.value should be ("Muchas problemas")

    Or, using assertions instead of matcher expressions:

    assert(either1.right.value > 9)
assert(either2.left.value === "Muchas problemas")

    Were you to simply invoke right.get or left.get on the Either, if the Either wasn't defined as expected (e.g., it was a Left when you expected a Right), it would throw a NoSuchElementException:

    val either: Either[String, Int] = Left("Muchas problemas")

either.right.get should be > 9 // either.right.get throws NoSuchElementException

    The NoSuchElementException would cause the test to fail, but without providing a stack depth pointing to the failing line of test code. This stack depth, provided by TestFailedException (and a few other ScalaTest exceptions), makes it quicker for users to navigate to the cause of the failure. Without EitherValues, to get a stack depth exception you would need to make two statements, like this:

    val either: Either[String, Int] = Left("Muchas problemas")

either should be ('right) // throws TestFailedException
either.right.get should be > 9

    The EitherValues trait allows you to state that more concisely:

    val either: Either[String, Int] = Left("Muchas problemas")

either.right.value should be > 9 // either.right.value throws TestFailedException

    Definition Classes
    scalatest
  • LeftValuable
  • RightValuable

class LeftValuable[L, R] extends AnyRef

Wrapper class that adds a value method to LeftProjection, allowing you to make statements like:

either.left.value should be > 9

Source
EitherValues.scala
Linear Supertypes
AnyRef, Any
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  1. LeftValuable
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Visibility
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Instance Constructors

  1. new LeftValuable(leftProj: LeftProjection[L, R], pos: Position)

    leftProj

    A LeftProjection to convert to LeftValuable, which provides the value method.

Value Members

  1. def value: L

    Returns the Left value contained in the wrapped LeftProjection, if defined as a Left, else throws TestFailedException with a detail message indicating the Either was defined as a Right, not a Left.

    Returns the Left value contained in the wrapped LeftProjection, if defined as a Left, else throws TestFailedException with a detail message indicating the Either was defined as a Right, not a Left.