FixtureContext

Marker trait for fixture-context objects, that enables them to be used in testing styles that require type Assertion

A fixture-context object is a way to share fixtures between different tests that is most useful when different tests need different combinations of fixture objects. The fixture-context object technique is only appropriate if you don't need to clean up the fixtures after using them.

To use this technique, you define instance variables intialized with fixture objects in traits and/or classes, then in each test instantiate an object that contains just the fixture objects needed by the test. Traits allow you to mix together just the fixture objects needed by each test, whereas classes allow you to pass data in via a constructor to configure the fixture objects. Here's an example FlatSpec in which fixture objects are partitioned into two traits and each test just mixes together the traits it needs:

package org.scalatest.examples.flatspec.fixturecontext

import collection.mutable.ListBuffer
import org.scalatest.FlatSpec
import org.scalatest.FixtureContext

class ExampleSpec extends FlatSpec {

 trait Builder extends FixtureContext {
   val builder = new StringBuilder("ScalaTest is ")
 }

 trait Buffer extends FixtureContext {
   val buffer = ListBuffer("ScalaTest", "is")
 }

 // This test needs the StringBuilder fixture
 "Testing" should "be productive" in new Builder {
   builder.append("productive!")
   assert(builder.toString === "ScalaTest is productive!")
 }

 // This test needs the ListBuffer[String] fixture
 "Test code" should "be readable" in new Buffer {
   buffer += ("readable!")
   assert(buffer === List("ScalaTest", "is", "readable!"))
 }

 // This test needs both the StringBuilder and ListBuffer
 it should "be clear and concise" in new Builder with Buffer {
   builder.append("clear!")
   buffer += ("concise!")
   assert(builder.toString === "ScalaTest is clear!")
   assert(buffer === List("ScalaTest", "is", "concise!"))
 }
}

Extending FixtureContext, which extends trait org.scalatest.compatible.Assertion makes it more convenient to use fixture-context objects in styles, such as async styles, that require test bodies to have type Assertion.