org.scalatest

BeforeAndAfterEach

trait BeforeAndAfterEach extends SuiteMixin

Stackable trait that can be mixed into suites that need code executed before and after running each test.

Recommended Usage: Use trait BeforeAndAfterEach when you want to stack traits that perform side-effects before and/or after tests, rather than at the beginning or end of tests, or when you need access to the config map or test name in the before and/or after code. Note: For more insight into where BeforeAndAfterEach fits into the big picture, see the Shared fixtures section in the documentation for your chosen style trait.

A test fixture is composed of the objects and other artifacts (files, sockets, database connections, etc.) tests use to do their work. When multiple tests need to work with the same fixtures, it is important to try and avoid duplicating the fixture code across those tests. The more code duplication you have in your tests, the greater drag the tests will have on refactoring the actual production code. Trait BeforeAndAfterEach offers one way to eliminate such code duplication: a beforeEach method that will be run before each test (like JUnit's setUp), and an afterEach method that will be run after (like JUnit's tearDown).

Here's an example:

package org.scalatest.examples.flatspec.composingbeforeandaftereach

import org.scalatest._
import collection.mutable.ListBuffer

trait Builder extends BeforeAndAfterEach { this: Suite =>

  val builder = new StringBuilder

  override def beforeEach() {
    builder.append("ScalaTest is ")
    super.beforeEach() // To be stackable, must call super.beforeEach
  }

  override def afterEach() {
    try {
      super.afterEach() // To be stackable, must call super.afterEach
    }
    finally {
      builder.clear()
    }
  }
}

trait Buffer extends BeforeAndAfterEach { this: Suite =>

  val buffer = new ListBuffer[String]

  override def afterEach() {
    try {
      super.afterEach() // To be stackable, must call super.afterEach
    }
    finally {
      buffer.clear()
    }
  }
}

class ExampleSpec extends FlatSpec with Builder with Buffer {

  "Testing" should "be easy" in {
    builder.append("easy!")
    assert(builder.toString === "ScalaTest is easy!")
    assert(buffer.isEmpty)
    buffer += "sweet"
  }

  it should "be fun" in {
    builder.append("fun!")
    assert(builder.toString === "ScalaTest is fun!")
    assert(buffer.isEmpty)
    buffer += "clear"
  }
}

To get the same ordering as withFixture, place your super.beforeEach call at the end of each beforeEach method, and the super.afterEach call at the beginning of each afterEach method, as shown in the previous example. It is a good idea to invoke super.afterEach in a try block and perform cleanup in a finally clause, as shown in the previous example, because this ensures the cleanup code is performed even if super.afterEach throws an exception.

Besides enabling trait stacking, the other main advantage of BeforeAndAfterEach over BeforeAndAfter is that BeforeAndAfterEach allows you to make use of test data (the test name and the config map) in your before and/or after code, whereas BeforeAndAfter does not. To access the test data, simply override the form of beforeEach and/or afterEach that takes a TestData parameter, like this.

override def beforeEach(td: TestData) {
  // Can now use the test data in your "before" code:
  //   td.name is the name of the test
  //   td.configMap is the config map passed to runTest
}

override def afterEach(td: TestData) {
  // Can now use the test data in your "after" code:
  //   td.name is the name of the test
  //   td.configMap is the config map passed to runTest
}

The main disadvantage of BeforeAndAfterEach compared to BeforeAndAfter is that BeforeAndAfterEach requires more boilerplate. If you don't need trait stacking or access to the test data, use BeforeAndAfter instead of BeforeAndAfterEach.

Self Type
BeforeAndAfterEach with Suite
Linear Supertypes
SuiteMixin, AnyRef, Any
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Abstract Value Members

  1. def expectedTestCount (filter: Filter): Int

    The total number of tests that are expected to run when this Suite's run method is invoked.

    The total number of tests that are expected to run when this Suite's run method is invoked.

    filter

    a Filter with which to filter tests to count based on their tags

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  2. def nestedSuites : IndexedSeq[Suite]

    An immutable IndexedSeq of this SuiteMixin object's nested Suites.

    An immutable IndexedSeq of this SuiteMixin object's nested Suites. If this SuiteMixin contains no nested Suites, this method returns an empty IndexedSeq.

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  3. def rerunner : Option[String]

    The fully qualified name of the class that can be used to rerun this suite.

    The fully qualified name of the class that can be used to rerun this suite.

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  4. def run (testName: Option[String], args: Args): Status

    Runs this suite of tests.

    Runs this suite of tests.

    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 Suite.

    args

    the Args for this run

    returns

    a Status object that indicates when all tests and nested suites started by this method have completed, and whether or not a failure occurred.

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  5. def runNestedSuites (args: Args): Status

    Runs zero to many of this suite's nested suites.

    Runs zero to many of this suite's nested suites.

    args

    the Args for this run

    returns

    a Status object that indicates when all nested suites started by this method have completed, and whether or not a failure occurred.

    Attributes
    protected abstract
    Definition Classes
    SuiteMixin

  6. def runTests (testName: Option[String], args: Args): Status

    Runs zero to many of this suite's tests.

    Runs zero to many of this suite's tests.

    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.

    args

    the Args for this run

    returns

    a Status object that indicates when all tests started by this method have completed, and whether or not a failure occurred.

    Attributes
    protected abstract
    Definition Classes
    SuiteMixin

  7. val styleName : String

    This suite's style name.

    This suite's style name.

    This lifecycle method provides a string that is used to determine whether this suite object's style is one of the chosen styles for the project.

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  8. def tags : Map[String, Set[String]]

    A Map whose keys are String tag names with which tests in this Suite are marked, and whose values are the Set of test names marked with each tag.

    A Map whose keys are String tag names with which tests in this Suite are marked, and whose values are the Set of test names marked with each tag. If this Suite contains no tags, this method returns an empty Map.

    Subclasses may implement this method to define and/or discover tags in a custom manner, but overriding method implementations should never return an empty Set as a value. If a tag has no tests, its name should not appear as a key in the returned Map.

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  9. def testNames : Set[String]

    A Set of test names.

    A Set of test names. If this Suite contains no tests, this method returns an empty Set.

    Although subclass and subtrait implementations of this method may return a Set whose iterator produces String test names in a well-defined order, the contract of this method does not required a defined order. Subclasses are free to implement this method and return test names in either a defined or undefined order.

    Attributes
    abstract
    Definition Classes
    SuiteMixin

  10. def withFixture (test: NoArgTest): Unit

    Runs the passed test function with a fixture established by this method.

    Runs the passed test function with a fixture established by this method.

    This method should set up the fixture needed by the tests of the current suite, invoke the test function, and if needed, perform any clean up needed after the test completes. Because the NoArgTest function passed to this method takes no parameters, preparing the fixture will require side effects, such as initializing an external database.

    test

    the no-arg test function to run with a fixture

    Attributes
    protected abstract
    Definition Classes
    SuiteMixin