scalatestCoreDotty/org.scalatest/BeforeAndAfterEach

BeforeAndAfterEach

trait BeforeAndAfterEach extends SuiteMixin

Stackable trait that can be mixed into suites that need code executed before and/or 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. 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, and the slower your compile will likely be. 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.

The main advantage of BeforeAndAfterEach over BeforeAndAfter is that BeforeAndAfterEach. enables trait stacking. The main disadvantage of BeforeAndAfterEach compared to BeforeAndAfter is that BeforeAndAfterEach requires more boilerplate. If you don't need trait stacking, use BeforeAndAfter instead of BeforeAndAfterEach. If you want to make use of test data (the test name, config map, etc.) in your beforeEach or afterEach method, use trait BeforeAndAfterEachTestData instead.

trait SuiteMixin

class Object

trait Matchable

class Any

Suite

Value members

Concrete methods

Defines a method to be run after each of this suite's tests.

This trait's implementation of runTest invokes this method after invoking super.runTest. Thus this method can be used to tear down a test fixture needed by each test, after each test completes execution.

This trait's implementation of this method does nothing.

Defines a method to be run before each of this suite's tests.

This trait's implementation of runTest invokes this method before invoking super.runTest. Thus this method can be used to set up a test fixture needed by each test, before each test begins execution.

This trait's implementation of this method does nothing.

Runs a test surrounded by calls to beforeEach() and afterEach().

This trait's implementation of this method ("this method") invokes beforeEach() before running each test and afterEach() after running each test. It runs each test by invoking super.runTest, passing along the two parameters passed to it.

If any invocation of beforeEach() completes abruptly with an exception, this method will complete abruptly with the same exception, however, before doing so, it will invoke afterEach(). If beforeEach() returns normally, but the subsequent call to super.runTest completes abruptly with an exception, this method will complete abruptly with the same exception, however, before doing so, it will invoke afterEach(). If afterEach() completes abruptly with an exception, this method will nevertheless complete abruptly with an exception previously thrown by either beforeEach() or super.runTest. If both beforeEach() and super.runTest return normally, but afterEach() completes abruptly with an exception, this method will complete abruptly with the exception thrown by afterEach().

The reason this method invokes afterEach() even if beforeEach() or super.runTest throws an exception is to reduce the chance that a resource acquired by beforeEach() or super.runTest prior to completing abruptly with the exception is not cleaned up and therefore leaked.

Value parameters:

args: the Args for this run
testName: the name of one test to run.

Returns:

a Status object that indicates when the test started by this method has completed, and whether or not it failed .

Inherited methods

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

Value parameters:

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

Inherited from:

SuiteMixin

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

Inherited from:: SuiteMixin

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

Inherited from:: SuiteMixin

Runs this suite of tests.

Value parameters:

args: the Args for this run
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.

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.

Throws:

NullArgumentException: if any passed parameter is null.

Inherited from:

SuiteMixin

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

Value parameters:

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.

Throws:

NullArgumentException: if args is null.

Inherited from:

SuiteMixin

Runs zero to many of this suite's tests.

Value parameters:

args: the Args for this run
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.

Returns:

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

Throws:

NullArgumentException: if either testName or args is null.

Inherited from:

SuiteMixin

A string ID for this Suite that is intended to be unique among all suites reported during a run.

The suite ID is intended to be unique, because ScalaTest does not enforce that it is unique. If it is not unique, then you may not be able to uniquely identify a particular test of a particular suite. This ability is used, for example, to dynamically tag tests as having failed in the previous run when rerunning only failed tests.

Returns:: this Suite object's ID.
Inherited from:: SuiteMixin

A user-friendly suite name for this Suite.

This trait's implementation of this method returns the simple name of this object's class. This trait's implementation of runNestedSuites calls this method to obtain a name for Reports to pass to the suiteStarting, suiteCompleted, and suiteAborted methods of the Reporter.

Returns:: this Suite object's suite name.
Inherited from:: SuiteMixin

A Map whose keys are String names of tagged tests and whose associated values are the Set of tag names for the test. If a test has no associated tags, its name does not appear as a key in the returned Map. If this Suite contains no tests with tags, this method returns an empty Map.

Subclasses may override 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 test has no tags, its name should not appear as a key in the returned Map.

Inherited from:: SuiteMixin

Provides a TestData instance for the passed test name, given the passed config map.

This method is used to obtain a TestData instance to pass to withFixture(NoArgTest) and withFixture(OneArgTest) and the beforeEach and afterEach methods of trait BeforeAndAfterEach.

Value parameters:

testName: the name of the test for which to return a TestData instance
theConfigMap: the config map to include in the returned TestData

Returns:

a TestData instance for the specified test, which includes the specified config map

Inherited from:

SuiteMixin

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.

Inherited from:: SuiteMixin

Deprecated and Inherited fields

@deprecated("The styleName lifecycle method has been deprecated and will be removed in a future version of ScalaTest with no replacement.", "3.1.0")

The styleName lifecycle method has been deprecated and will be removed in a future version of ScalaTest.

This method was used to support the chosen styles feature, which was deactivated in 3.1.0. The internal modularization of ScalaTest in 3.2.0 will replace chosen styles as the tool to encourage consistency across a project. We do not plan a replacement for styleName.

Deprecated
Inherited from:: SuiteMixin