org.scalatest.BeforeAndAfter

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

Recommended Usage: Use trait BeforeAndAfter when you need to perform the same side-effects before and/or after tests, rather than at the beginning or end of tests. Note: For more insight into where BeforeAndAfter 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 BeforeAndAfter offers one way to eliminate such code duplication: a before clause that will register code to be run before each test, and an after clause that will register code to be run after.

Here's an example:

package org.scalatest.examples.flatspec.beforeandafter

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

class ExampleSpec extends FlatSpec with BeforeAndAfter {

  val builder = new StringBuilder
  val buffer = new ListBuffer[String]

  before {
    builder.append("ScalaTest is ")
  }

  after {
    builder.clear()
    buffer.clear()
  }

  "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)
  }
}

The before and after methods can each only be called once per Suite, and cannot be invoked after run has been invoked. If either of the registered before or after functions complete abruptly with an exception, it will be reported as an aborted suite and no more tests will be attempted in that suite.

Note that the only way before and after code can communicate with test code is via some side-effecting mechanism, commonly by reassigning instance vars or by changing the state of mutable objects held from instance vals (as in this example). If using instance vars or mutable objects held from instance vals you wouldn't be able to run tests in parallel in the same instance of the test class unless you synchronized access to the shared, mutable state. This is why ScalaTest's ParallelTestExecution trait extends OneInstancePerTest. By running each test in its own instance of the class, each test has its own copy of the instance variables, so you don't need to synchronize. Were you to mix ParallelTestExecution into the ExampleSuite above, the tests would run in parallel just fine without any synchronization needed on the mutable StringBuilder and ListBuffer[String] objects.

Although BeforeAndAfter provides a minimal-boilerplate way to execute code before and after tests, it isn't designed to enable stackable traits, because the order of execution would be non-obvious. If you want to factor out before and after code that is common to multiple test suites, you should use trait BeforeAndAfterEach instead.

The advantage this trait has over BeforeAndAfterEach is that its syntax is more concise. The main disadvantage is that it is not stackable, whereas BeforeAndAfterEach is. I.e., you can write several traits that extend BeforeAndAfterEach and provide beforeEach methods that include a call to super.beforeEach, and mix them together in various combinations. By contrast, only one call to the before registration function is allowed in a suite or spec that mixes in BeforeAndAfter. In addition, BeforeAndAfterEach allows you to access the config map and test name via the TestData passed to its beforeEach and afterEach methods, whereas BeforeAndAfter gives you no access to the config map.

Self Type: BeforeAndAfter with Suite

Linear Supertypes

SuiteMixin, AnyRef, Any

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BeforeAndAfter
SuiteMixin
AnyRef
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Abstract Value Members

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
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
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
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
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
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
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
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
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

Concrete Value Members

def != (arg0: AnyRef): Boolean

Attributes
final
Definition Classes
AnyRef
def != (arg0: Any): Boolean

Attributes
final
Definition Classes
Any
def ## (): Int

Attributes
final
Definition Classes
AnyRef → Any
def == (arg0: AnyRef): Boolean

Attributes
final
Definition Classes
AnyRef
def == (arg0: Any): Boolean

Attributes
final
Definition Classes
Any
def after (fun: ⇒ Any): Unit

Registers code to be executed after each of this suite's tests.
Registers code to be executed after each of this suite's tests.
This trait's implementation of runTest executes the code passed to this method after running each test. Thus the code passed to this method can be used to tear down a test fixture needed by each test.

Attributes
protected
def asInstanceOf [T0] : T0

Attributes
final
Definition Classes
Any
def before (fun: ⇒ Any): Unit

Registers code to be executed before each of this suite's tests.
Registers code to be executed before each of this suite's tests.
This trait's implementation of runTest executes the code passed to this method before running each test. Thus the code passed to this method can be used to set up a test fixture needed by each test.

Attributes
protected
def clone (): AnyRef

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws()
def eq (arg0: AnyRef): Boolean

Attributes
final
Definition Classes
AnyRef
def equals (arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize (): Unit

Attributes
protected[lang]
Definition Classes
AnyRef
Annotations
@throws()
def getClass (): java.lang.Class[_]

Attributes
final
Definition Classes
AnyRef
def hashCode (): Int

Definition Classes
AnyRef → Any
def isInstanceOf [T0] : Boolean

Attributes
final
Definition Classes
Any
def ne (arg0: AnyRef): Boolean

Attributes
final
Definition Classes
AnyRef
def notify (): Unit

Attributes
final
Definition Classes
AnyRef
def notifyAll (): Unit

Attributes
final
Definition Classes
AnyRef
def run (testName: Option[String], args: Args): Status

This trait's implementation of run sets a flag indicating run has been invoked, after which any invocation to before or after will complete abruptly with a NotAllowedException.
This trait's implementation of run sets a flag indicating run has been invoked, after which any invocation to before or after will complete abruptly with a NotAllowedException.
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 and nested suites started by this method have completed, and whether or not a failure occurred.

Definition Classes
BeforeAndAfter → SuiteMixin
def runTest (testName: String, args: Args): Status

Run a test surrounded by calls to the code passed to before and after, if any.
Run a test surrounded by calls to the code passed to before and after, if any.
This trait's implementation of this method ("this method") invokes the function registered with before, if any, before running each test and the function registered with after, if any, after running each test. It runs each test by invoking super.runTest, passing along the five parameters passed to it.
If any invocation of the function registered with before completes abruptly with an exception, this method will complete abruptly with the same exception. If any 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 the function registered with after, if any. If the function registered with after also completes abruptly with an exception, this method will nevertheless complete abruptly with the exception previously thrown by super.runTest. If super.runTest returns normally, but the function registered with after completes abruptly with an exception, this method will complete abruptly with the exception thrown by the function registered with after.
testName
the name of one test to run.
args
the Args for this run
returns
a Status object that indicates when the test started by this method has completed, and whether or not it failed .

Attributes
protected
Definition Classes
BeforeAndAfter → SuiteMixin
def synchronized [T0] (arg0: ⇒ T0): T0

Attributes
final
Definition Classes
AnyRef
def toString (): String

Definition Classes
AnyRef → Any
def wait (): Unit

Attributes
final
Definition Classes
AnyRef
Annotations
@throws()
def wait (arg0: Long, arg1: Int): Unit

Attributes
final
Definition Classes
AnyRef
Annotations
@throws()
def wait (arg0: Long): Unit

Attributes
final
Definition Classes
AnyRef
Annotations
@throws()

BeforeAndAfter

trait BeforeAndAfter extends SuiteMixin

Abstract Value Members

def expectedTestCount (filter: Filter): Int

def nestedSuites : IndexedSeq[Suite]

def rerunner : Option[String]

def runNestedSuites (args: Args): Status

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

val styleName : String

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

def testNames : Set[String]

def withFixture (test: NoArgTest): Unit

Concrete Value Members

def != (arg0: AnyRef): Boolean

def != (arg0: Any): Boolean

def ## (): Int

def == (arg0: AnyRef): Boolean

def == (arg0: Any): Boolean

def after (fun: ⇒ Any): Unit

def asInstanceOf [T0] : T0

def before (fun: ⇒ Any): Unit

def clone (): AnyRef

def eq (arg0: AnyRef): Boolean

def equals (arg0: Any): Boolean

def finalize (): Unit

def getClass (): java.lang.Class[_]

def hashCode (): Int

def isInstanceOf [T0] : Boolean

def ne (arg0: AnyRef): Boolean

def notify (): Unit

def notifyAll (): Unit

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

def runTest (testName: String, args: Args): Status

def synchronized [T0] (arg0: ⇒ T0): T0

def toString (): String

def wait (): Unit

def wait (arg0: Long, arg1: Int): Unit

def wait (arg0: Long): Unit

Inherited from SuiteMixin

Inherited from AnyRef

Inherited from Any