org.scalatest.NonImplicitAssertions.scala Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of scalatest_2.11.0-M3 Show documentation
ScalaTest is a free, open-source testing toolkit for Scala and Java programmers.
There is a newer version: 2.0.M6-SNAP27
/*
 * Copyright 2001-2011 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

/**
 * Trait that can be mixed into a Suite to disable the lone implicit conversion provided by default in trait
 * Assertions, which trait Suite extends.
 * 
 * 
 * Currently there is just one implicit conversion provided by default in Suite, the one that adds a === method to
 * anything. If more default implicits are added to Suite in future versions of ScalaTest, they will be added here as well so that
 * this trait will disable all of them.
 * 
 *
 * 
 * This trait can be used to quickly solve a problem in which ScalaTest's default implicit conversion is clashing with those of some other library
 * you need to use in your tests. After mixing in this trait, like this:
 * 
 * 
 *  * class MySuite extends FunSuite with NonImplicitAssertions { 
 *   // ... 
 * } 
 * 
 *
 * 
 * You can write tests using assert (without triple equals), expect, and intercept:
 * 
 *
 *  *   assert(a < 7)
 *
 *   expect(2) { 1 + 1 }
 *
 *   intercept[IndexOutOfBoundsException] {
 *     "hi".charAt(-1)
 *   }
 * 
 *
 * @author Chua Chee Seng
 * @author Bill Venners
 */
trait NonImplicitAssertions extends Assertions {

  /**
   * Overrides the super implementation of convertToEqualizer, turning off the implicit 
   * modifier (if present) to remove the method from the space of implicit conversions.
   *
   * @param left the object whose type to convert to Equalizer.
   * @throws NullPointerException if left is null.
   */
  override def convertToEqualizer(right: Any): Equalizer = super.convertToEqualizer(right)
  // override def convertToEqualizer(right: Any): Equalizer = new Equalizer(right)
}

/**
 * Companion object that facilitates the importing of the members of trait Assertions without importing the implicit conversions
 * it provides by default.  One use case for this object is to import the non-implicit Assertions members so you can use
 * them in the Scala interpreter along with another library whose implicits conflict with those provided by Assertions:
 *
 *  * $ scala -cp scalatest-1.7.jar
 * Welcome to Scala version 2.9.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_29).
 * Type in expressions to have them evaluated.
 * Type :help for more information.
 * 
 * scala> import org.scalatest._
 * import org.scalatest._
 * 
 * scala> import NonImplicitAssertions._
 * import NonImplicitAssertions._
 * 
 * scala> assert(1 + 1 === 2)
 * <console>:14: error: value === is not a member of Int
 *              assert(1 + 1 === 2)
 *                            ^
 * 
 * scala> assert(1 + 1 == 2)
 *
 * scala> expect(2) { 1 + 1 }
 * 
 * scala> expect(2) { 1 + 1 + 1 }
 * org.scalatest.TestFailedException: Expected 2, but got 3
 *   at org.scalatest.Assertions$class.newAssertionFailedException(Assertions.scala:318)
 *   at org.scalatest.NonImplicitAssertions$.newAssertionFailedException(NonImplicitAssertions.scala:73)
 *   ...
 * 
 * scala> intercept[IndexOutOfBoundsException] { "hi".charAt(-1) }
 * res3: IndexOutOfBoundsException = java.lang.StringIndexOutOfBoundsException: String index out of range: -1
 * 
 */
object NonImplicitAssertions extends NonImplicitAssertions