org.scalatest.fixture

trait FixtureWordSpec

[source: org/scalatest/fixture/FixtureWordSpec.scala]

trait FixtureWordSpec
extends FixtureSuite with ShouldVerb with MustVerb with CanVerb
A sister trait to org.scalatest.WordSpec that can pass a fixture object into its tests.

This trait behaves similarly to trait org.scalatest.WordSpec, except that tests may take a fixture object. The type of the fixture object passed is defined by the abstract Fixture type, which is declared as a member of this trait (inherited from supertrait FixtureSuite). This trait also inherits the abstract method withFixture from supertrait FixtureSuite. The withFixture method takes a OneArgTest, which is a nested trait defined as a member of supertrait FixtureSuite. OneArgTest has an apply method that takes a Fixture. This apply method is responsible for running a test. This trait's runTest method delegates the actual running of each test to withFixture, passing in the test code to run via the OneArgTest argument. The withFixture method (abstract in this trait) is responsible for creating the fixture and passing it to the test function.

Subclasses of this trait must, therefore, do three things differently from a plain old org.scalatest.WordSpec:

  1. define the type of the fixture object by specifying type Fixture
  2. define the withFixture method
  3. write tests that take a Fixture (You can also define tests that don't take a Fixture.)

Here's an example:

 import org.scalatest.fixture.FixtureWordSpec
 import java.io.FileReader
 import java.io.FileWriter
 import java.io.File
 
 class MyWordSpec extends FixtureWordSpec {

   // 1. define type FixtureParam
   type FixtureParam = FileReader

   // 2. define the withFixture method
   def withFixture(test: OneArgTest) {

     val FileName = "TempFile.txt"

     // Set up the temp file needed by the test
     val writer = new FileWriter(FileName)
     try {
       writer.write("Hello, test!")
     }
     finally {
       writer.close()
     }

     // Create the reader needed by the test
     val reader = new FileReader(FileName)
  
     try {
       // Run the test using the temp file
       test(reader)
     }
     finally {
       // Close and delete the temp file
       reader.close()
       val file = new File(FileName)
       file.delete()
     }
   }
 
   // 3. write tests that take a fixture parameter
   "A contrived example" should {
     "read from the temp file" in { reader =>
       var builder = new StringBuilder
       var c = reader.read()
       while (c != -1) {
         builder.append(c.toChar)
         c = reader.read()
       }
       assert(builder.toString === "Hello, test!")
     }
 
     "read the first char of the temp file" in { reader =>
       assert(reader.read() === 'H')
     }
 
     // (You can also write tests that don't take a fixture parameter.)
     "not be required" in {
       without fixture {
         assert(1 + 1 === 2)
       }
     }
   }
 }
 

If the fixture you want to pass into your tests consists of multiple objects, you will need to combine them into one object to use this trait. One good approach to passing multiple fixture objects is to encapsulate them in a tuple. Here's an example that takes the tuple approach:

 import org.scalatest.fixture.FixtureWordSpec
 import scala.collection.mutable.ListBuffer

 class MyWordSpec extends FixtureWordSpec {

   type FixtureParam = (StringBuilder, ListBuffer[String])

   def withFixture(test: OneArgTest) {

     // Create needed mutable objects
     val stringBuilder = new StringBuilder("ScalaTest is ")
     val listBuffer = new ListBuffer[String]

     // Invoke the test function, passing in the mutable objects
     test(stringBuilder, listBuffer)
   }

   "Another contrived example" should {
     "mutate shared fixture objects" in { fixture =>
       val (builder, buffer) = fixture
       builder.append("easy!")
       assert(builder.toString === "ScalaTest is easy!")
       assert(buffer.isEmpty)
       buffer += "sweet"
     }

     "get a fresh set of mutable fixture objects" in { fixture =>
       val (builder, buffer) = fixture
       builder.append("fun!")
       assert(builder.toString === "ScalaTest is fun!")
       assert(buffer.isEmpty)
     }
   }
 }
 

When using a tuple to pass multiple fixture objects, it is usually helpful to give names to each individual object in the tuple with a pattern-match assignment, as is done at the beginning of each test here with:

 val (builder, buffer) = fixture
 

Another good approach to passing multiple fixture objects is to encapsulate them in a case class. Here's an example that takes the case class approach:

 import org.scalatest.fixture.FixtureWordSpec
 import scala.collection.mutable.ListBuffer

 class MyWordSpec extends FixtureWordSpec {

   case class FixtureHolder(builder: StringBuilder, buffer: ListBuffer[String])

   type FixtureParam = FixtureHolder

   def withFixture(test: OneArgTest) {

     // Create needed mutable objects
     val stringBuilder = new StringBuilder("ScalaTest is ")
     val listBuffer = new ListBuffer[String]

     // Invoke the test function, passing in the mutable objects
     test(FixtureHolder(stringBuilder, listBuffer))
   }

   "Another contrived example" should {
     "mutate shared fixture objects" in { fixture =>
       import fixture._
       builder.append("easy!")
       assert(builder.toString === "ScalaTest is easy!")
       assert(buffer.isEmpty)
       buffer += "sweet"
     }

     "get a fresh set of mutable fixture objects" in { fixture =>
       fixture.builder.append("fun!")
       assert(fixture.builder.toString === "ScalaTest is fun!")
       assert(fixture.buffer.isEmpty)
     }
   }
 }
 

When using a case class to pass multiple fixture objects, it can be helpful to make the names of each individual object available as a single identifier with an import statement. This is the approach taken by the testEasy method in the previous example. Because it imports the members of the fixture object, the test code can just use them as unqualified identifiers:

 "mutate shared fixture objects" in { fixture =>
   import fixture._
   builder.append("easy!")
   assert(builder.toString === "ScalaTest is easy!")
   assert(buffer.isEmpty)
   buffer += "sweet"
 }
 

Alternatively, you may sometimes prefer to qualify each use of a fixture object with the name of the fixture parameter. This approach, taken by the testFun method in the previous example, makes it more obvious which variables in your test are part of the passed-in fixture:

 "get a fresh set of mutable fixture objects" in { fixture =>
   fixture.builder.append("fun!")
   assert(fixture.builder.toString === "ScalaTest is fun!")
   assert(fixture.buffer.isEmpty)
 }
 

Configuring fixtures and tests

Sometimes you may want to write tests that are configurable. For example, you may want to write a suite of tests that each take an open temp file as a fixture, but whose file name is specified externally so that the file name can be can be changed from run to run. To accomplish this the OneArgTest trait has a configMap method, which will return a Map[String, Any] from which configuration information may be obtained. The runTest method of this trait will pass a OneArgTest to withFixture whose configMap method returns the configMap passed to runTest. Here's an example in which the name of a temp file is taken from the passed configMap:

 import org.scalatest.fixture.FixtureWordSpec
 import java.io.FileReader
 import java.io.FileWriter
 import java.io.File
 
 class MyWordSpec extends FixtureWordSpec {

   type FixtureParam = FileReader

   def withFixture(test: OneArgTest) {

     require(
       test.configMap.contains("TempFileName"),
       "This suite requires a TempFileName to be passed in the configMap"
     )

     // Grab the file name from the configMap
     val FileName = test.configMap("TempFileName")

     // Set up the temp file needed by the test
     val writer = new FileWriter(FileName)
     try {
       writer.write("Hello, test!")
     }
     finally {
       writer.close()
     }

     // Create the reader needed by the test
     val reader = new FileReader(FileName)
  
     try {
       // Run the test using the temp file
       test(reader)
     }
     finally {
       // Close and delete the temp file
       reader.close()
       val file = new File(FileName)
       file.delete()
     }
   }
 
   "A contrived example" should {
     "read from the temp file" in { reader =>
       var builder = new StringBuilder
       var c = reader.read()
       while (c != -1) {
         builder.append(c.toChar)
         c = reader.read()
       }
       assert(builder.toString === "Hello, test!")
     }
 
     "read the first char of the temp file" in { reader =>
       assert(reader.read() === 'H')
     }
   }
 }
 

If you want to pass into each test the entire configMap that was passed to runTest, you can mix in trait ConfigMapFixture. See the documentation for ConfigMapFixture for the details, but here's a quick example of how it looks:

  import org.scalatest.fixture.FixtureWordSpec
  import org.scalatest.fixture.ConfigMapFixture

  class MyWordSpec extends FixtureWordSpec with ConfigMapFixture {

    "The final contrived example" should {
      "contain hello" in { configMap =>
        // Use the configMap passed to runTest in the test
        assert(configMap.contains("hello")
      }

      "contain world" in { configMap =>
        assert(configMap.contains("world")
      }
    }
  }
 

ConfigMapFixture can also be used to facilitate writing FixtureWordSpecs that include tests that take different fixture types. See the documentation for MultipleFixtureWordSpec for more information.

Author
Bill Venners
Direct Known Subclasses:
MultipleFixtureWordSpec

Value Summary
protected val behave : BehaveWord
Supports shared test registration in FixtureWordSpecs.
protected implicit val subjectRegistrationFunction : StringVerbBlockRegistration
Supports the registration of subjects.
protected implicit val subjectWithAfterWordRegistrationFunction : (java.lang.String, java.lang.String, ResultOfAfterWordApplication) => Unit
Supports the registration of subject descriptions with after words.
Method Summary
protected def afterWord (text : java.lang.String) : AfterWord
Creates an after word that an be used to reduce text duplication.
protected implicit def convertToWordSpecStringWrapper (s : java.lang.String) : WordSpecStringWrapper
Implicitly converts Strings to WordSpecStringWrapper, which enables methods when, that, in, is, taggedAs and ignore to be invoked on Strings.
protected implicit def info : Informer
Returns an Informer that during test execution will forward strings (and other objects) passed to its apply method to the current reporter. If invoked in a constructor, it will register the passed string for forwarding later during test execution. If invoked while this FixtureWordSpec is being executed, such as from inside a test function, it will forward the information to the current reporter immediately. If invoked at any other time, it will throw an exception. This method can be called safely by any thread.
override def run (testName : scala.Option[java.lang.String], reporter : Reporter, stopper : Stopper, filter : Filter, configMap : scala.collection.immutable.Map[java.lang.String, Any], distributor : scala.Option[Distributor], tracker : Tracker) : Unit
Runs this suite of tests.
protected override def runTest (testName : java.lang.String, reporter : Reporter, stopper : Stopper, configMap : scala.collection.immutable.Map[java.lang.String, Any], tracker : Tracker) : Unit
Run a test. This trait's implementation runs the test registered with the name specified by testName. Each test's name is a concatenation of the text of all describers surrounding a test, from outside in, and the test's spec text, with one space placed between each item. (See the documenation for testNames for an example.)
protected override def runTests (testName : scala.Option[java.lang.String], reporter : Reporter, stopper : Stopper, filter : Filter, configMap : scala.collection.immutable.Map[java.lang.String, Any], distributor : scala.Option[Distributor], tracker : Tracker) : Unit
override def tags : scala.collection.immutable.Map[java.lang.String, scala.collection.immutable.Set[java.lang.String]]
A Map whose keys are String tag names to which tests in this Spec belong, and values the Set of test names that belong to each tag. If this WordSpec contains no tags, this method returns an empty Map.
override def testNames : scala.collection.immutable.Set[java.lang.String]
An immutable Set of test names. If this FixtureWordSpec contains no tests, this method returns an empty Set.
Methods inherited from CanVerb
convertToStringCanWrapper
Methods inherited from MustVerb
convertToStringMustWrapper
Methods inherited from ShouldVerb
convertToStringShouldWrapper
Methods inherited from Suite
nestedSuites, execute, execute, execute, execute, groups, withFixture, runNestedSuites, suiteName, pending, pendingUntilFixed, expectedTestCount
Methods inherited from Assertions
assert, assert, assert, assert, convertToEqualizer, intercept, expect, expect, fail, fail, fail, fail
Methods inherited from AnyRef
getClass, hashCode, equals, clone, toString, notify, notifyAll, wait, wait, wait, finalize, ==, !=, eq, ne, synchronized
Methods inherited from Any
==, !=, isInstanceOf, asInstanceOf
Methods inherited from FixtureSuite
withFixture (abstract)
Class Summary
protected final class AfterWord (text : java.lang.String) extends AnyRef
Class whose instances are after words, which can be used to reduce text duplication.
protected final class ResultOfTaggedAsInvocationOnString (specText : java.lang.String, tags : scala.List[Tag]) extends AnyRef
Class that supports the registration of tagged tests.
protected final class WordSpecStringWrapper (string : java.lang.String) extends AnyRef
A class that via an implicit conversion (named convertToWordSpecStringWrapper) enables methods when, that, in, is, taggedAs and ignore to be invoked on Strings.
Value Details
protected implicit val subjectRegistrationFunction : StringVerbBlockRegistration
Supports the registration of subjects.

For example, this method enables syntax such as the following:

   "A Stack" should { ...
             ^
   

This function is passed as an implicit parameter to a should method provided in ShouldVerb, a must method provided in MustVerb, and a can method provided in CanVerb. When invoked, this function registers the subject and executes the block.


protected implicit val subjectWithAfterWordRegistrationFunction : (java.lang.String, java.lang.String, ResultOfAfterWordApplication) => Unit
Supports the registration of subject descriptions with after words.

For example, this method enables syntax such as the following:

   def provide = afterWord("provide")
  
   "The ScalaTest Matchers DSL" can provide { ... }
                                ^
   

This function is passed as an implicit parameter to a should method provided in ShouldVerb, a must method provided in MustVerb, and a can method provided in CanVerb. When invoked, this function registers the subject and executes the block.


protected val behave : BehaveWord
Supports shared test registration in FixtureWordSpecs.

This field enables syntax such as the following:

   behave like nonFullStack(stackWithOneItem)
   ^
   

For more information and examples of the use of behave, see the Shared tests section in the main documentation for trait WordSpec.


Method Details
protected implicit def info : Informer
Returns an Informer that during test execution will forward strings (and other objects) passed to its apply method to the current reporter. If invoked in a constructor, it will register the passed string for forwarding later during test execution. If invoked while this FixtureWordSpec is being executed, such as from inside a test function, it will forward the information to the current reporter immediately. If invoked at any other time, it will throw an exception. This method can be called safely by any thread.

protected def afterWord(text : java.lang.String) : AfterWord
Creates an after word that an be used to reduce text duplication.

If you are repeating a word or phrase at the beginning of each string inside a block, you can "move the word or phrase" out of the block with an after word. You create an after word by passing the repeated word or phrase to the afterWord method. Once created, you can place the after word after when, a verb (should, must, or can), or that. (You can't place one after in or is, the words that introduce a test.) Here's an example that has after words used in all three places:

   import org.scalatest.WordSpec
   
   class ScalaTestGUISpec extends WordSpec {
   
     def theUser = afterWord("the user")
     def display = afterWord("display")
     def is = afterWord("is")
   
     "The ScalaTest GUI" when theUser {
       "clicks on an event report in the list box" should display {
         "a blue background in the clicked-on row in the list box" in {}
         "the details for the event in the details area" in {}
         "a rerun button" that is {
           "enabled if the clicked-on event is rerunnable" in {}
           "disabled if the clicked-on event is not rerunnable" in {}
         }
       }
     }
   }
   

Running the previous WordSpec in the Scala interpreter would yield:

   scala> (new ScalaTestGUISpec).run()
   The ScalaTest GUI (when the user clicks on an event report in the list box) 
   - should display a blue background in the clicked-on row in the list box
   - should display the details for the event in the details area
   - should display a rerun button that is enabled if the clicked-on event is rerunnable
   - should display a rerun button that is disabled if the clicked-on event is not rerunnable
   

protected implicit def convertToWordSpecStringWrapper(s : java.lang.String) : WordSpecStringWrapper
Implicitly converts Strings to WordSpecStringWrapper, which enables methods when, that, in, is, taggedAs and ignore to be invoked on Strings.

override def tags : scala.collection.immutable.Map[java.lang.String, scala.collection.immutable.Set[java.lang.String]]
A Map whose keys are String tag names to which tests in this Spec belong, and values the Set of test names that belong to each tag. If this WordSpec contains no tags, this method returns an empty Map.

This trait's implementation returns tags that were passed as strings contained in Tag objects passed to methods test and ignore.

Overrides
FixtureSuite.tags

protected override def runTest(testName : java.lang.String, reporter : Reporter, stopper : Stopper, configMap : scala.collection.immutable.Map[java.lang.String, Any], tracker : Tracker) : Unit
Run a test. This trait's implementation runs the test registered with the name specified by testName. Each test's name is a concatenation of the text of all describers surrounding a test, from outside in, and the test's spec text, with one space placed between each item. (See the documenation for testNames for an example.)
Parameters
testName - the name of one test to execute.
reporter - the Reporter to which results will be reported
stopper - the Stopper that will be consulted to determine whether to stop execution early.
configMap - a Map of properties that can be used by this Spec's executing tests.
Throws
NullPointerException - if any of testName, reporter, stopper, or configMap is null.
Overrides
FixtureSuite.runTest

protected override def runTests(testName : scala.Option[java.lang.String], reporter : Reporter, stopper : Stopper, filter : Filter, configMap : scala.collection.immutable.Map[java.lang.String, Any], distributor : scala.Option[Distributor], tracker : Tracker) : Unit

Run zero to many of this Spec's tests.

This method takes a testName parameter that optionally specifies a test to invoke. If testName is Some, this trait's implementation of this method invokes runTest on this object, passing in:

  • testName - the String value of the testName Option passed to this method
  • reporter - the Reporter passed to this method, or one that wraps and delegates to it
  • stopper - the Stopper passed to this method, or one that wraps and delegates to it
  • configMap - the configMap passed to this method, or one that wraps and delegates to it

This method takes a Set of tag names that should be included (tagsToInclude), and a Set that should be excluded (tagsToExclude), when deciding which of this Suite's tests to execute. If tagsToInclude is empty, all tests will be executed except those those belonging to tags listed in the tagsToExclude Set. If tagsToInclude is non-empty, only tests belonging to tags mentioned in tagsToInclude, and not mentioned in tagsToExclude will be executed. However, if testName is Some, tagsToInclude and tagsToExclude are essentially ignored. Only if testName is None will tagsToInclude and tagsToExclude be consulted to determine which of the tests named in the testNames Set should be run. For more information on trait tags, see the main documentation for this trait.

If testName is None, this trait's implementation of this method invokes testNames on this Suite to get a Set of names of tests to potentially execute. (A testNames value of None essentially acts as a wildcard that means all tests in this Suite that are selected by tagsToInclude and tagsToExclude should be executed.) For each test in the testName Set, in the order they appear in the iterator obtained by invoking the elements method on the Set, this trait's implementation of this method checks whether the test should be run based on the tagsToInclude and tagsToExclude Sets. If so, this implementation invokes runTest, passing in:

  • testName - the String name of the test to run (which will be one of the names in the testNames Set)
  • reporter - the Reporter passed to this method, or one that wraps and delegates to it
  • stopper - the Stopper passed to this method, or one that wraps and delegates to it
  • configMap - the configMap passed to this method, or one that wraps and delegates to it
Parameters
testName - an optional name of one test to execute. If None, all relevant tests should be executed. I.e., None acts like a wildcard that means execute all relevant tests in this Spec.
reporter - the Reporter to which results will be reported
stopper - the Stopper that will be consulted to determine whether to stop execution early.
tagsToInclude - a Set of String tag names to include in the execution of this Spec
tagsToExclude - a Set of String tag names to exclude in the execution of this Spec
configMap - a Map of key-value pairs that can be used by this Spec's executing tests.
Throws
NullPointerException - if any of testName, reporter, stopper, tagsToInclude, tagsToExclude, or configMap is null.

override def testNames : scala.collection.immutable.Set[java.lang.String]
An immutable Set of test names. If this FixtureWordSpec contains no tests, this method returns an empty Set.

This trait's implementation of this method will return a set that contains the names of all registered tests. The set's iterator will return those names in the order in which the tests were registered. Each test's name is composed of the concatenation of the text of each surrounding describer, in order from outside in, and the text of the example itself, with all components separated by a space.

Overrides
FixtureSuite.testNames

override def run(testName : scala.Option[java.lang.String], reporter : Reporter, stopper : Stopper, filter : Filter, configMap : scala.collection.immutable.Map[java.lang.String, Any], distributor : scala.Option[Distributor], tracker : Tracker) : Unit
Runs this suite of tests.

If testName is None, this trait's implementation of this method calls these two methods on this object in this order:

  1. runNestedSuites(report, stopper, tagsToInclude, tagsToExclude, configMap, distributor)
  2. runTests(testName, report, stopper, tagsToInclude, tagsToExclude, configMap)

If testName is defined, then this trait's implementation of this method calls runTests, but does not call runNestedSuites. This behavior is part of the contract of this method. Subclasses that override run must take care not to call runNestedSuites if testName is defined. (The OneInstancePerTest trait depends on this behavior, for example.)

Subclasses and subtraits that override this run method can implement them without invoking either the runTests or runNestedSuites methods, which are invoked by this trait's implementation of this method. It is recommended, but not required, that subclasses and subtraits that override run in a way that does not invoke runNestedSuites also override runNestedSuites and make it final. Similarly it is recommended, but not required, that subclasses and subtraits that override run in a way that does not invoke runTests also override runTests (and runTest, which this trait's implementation of runTests calls) and make it final. The implementation of these final methods can either invoke the superclass implementation of the method, or throw an UnsupportedOperationException if appropriate. The reason for this recommendation is that ScalaTest includes several traits that override these methods to allow behavior to be mixed into a Suite. For example, trait BeforeAndAfterEach overrides runTestss. In a Suite subclass that no longer invokes runTests from run, the BeforeAndAfterEach trait is not applicable. Mixing it in would have no effect. By making runTests final in such a Suite subtrait, you make the attempt to mix BeforeAndAfterEach into a subclass of your subtrait a compiler error. (It would fail to compile with a complaint that BeforeAndAfterEach is trying to override runTests, which is a final method in your trait.)

Parameters
testName - an optional name of one test to run. If None, all relevant tests should be run. I.e., None acts like a wildcard that means run all relevant tests in this Suite.
reporter - the Reporter to which results will be reported
stopper - the Stopper that will be consulted to determine whether to stop execution early.
filter - a Filter with which to filter tests based on their tags
configMap - a Map of key-value pairs that can be used by the executing Suite of tests.
distributor - an optional Distributor, into which to put nested Suites to be run by another entity, such as concurrently by a pool of threads. If None, nested Suites will be run sequentially.
tracker - a Tracker tracking Ordinals being fired by the current thread.
Throws
NullPointerException - if any passed parameter is null.
IllegalArgumentException - if testName is defined, but no test with the specified test name exists in this Suite


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