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  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 LoneElement extends AnyRef

  Trait that provides an implicit conversion that adds to collection types a loneElement method, which will return the value of the lone element if the collection does indeed contain one and only one element, or throw TestFailedException if not.

  Trait that provides an implicit conversion that adds to collection types a loneElement method, which will return the value of the lone element if the collection does indeed contain one and only one element, or throw TestFailedException if not.

  This construct allows you to express in one statement that a collection should contain one and only one element and that the element value should meet some expectation. Here's an example:

  set.loneElement should be > 9
  

  Or, using an assertion instead of a matcher expression:

  assert(set.loneElement > 9)
  

  The loneElement syntax can be used with any collection type C for which an implicit Collecting[C] is available. ScalaTest provides implicit Collecting instances for scala.collection.GenTraversable, Array, and java.util.Collection. You can enable the loneElement syntax on other collection types by defining an implicit Collecting instances for those types.

  If you want to use loneElement with a java.util.Map, first transform it to a set of entries with entrySet, and if helpful, use ScalaTest's Entry class:

  scala> import org.scalatest._
  import org.scalatest._
  
  scala> import LoneElement._
  import LoneElement._
  
  scala> import Matchers._
  import Matchers._
  
  scala> val jmap = new java.util.HashMap[String, Int]
  jmap: java.util.HashMap[String,Int] = {}
  
  scala> jmap.put("one", 1)
  res0: Int = 0
  
  scala> jmap.entrySet.loneElement should be (Entry("one", 1))
  

  Definition Classes

  scalatest

• LoneElementCollectionWrapper
• LoneElementJavaMapWrapper
• LoneElementMapWrapper
• LoneElementStringWrapper

org.scalatest.LoneElement

LoneElementMapWrapper