ParallelTestExecution

Trait that causes that the tests of any suite it is mixed into to be run in parallel if a Distributor is passed to runTests.

ScalaTest's normal approach for running suites of tests in parallel is to run different suites in parallel, but the tests of any one suite sequentially. This approach should provide sufficient distribution of the work load in most cases, but some suites may encapsulate multiple long-running tests. Such suites may dominate the execution time of the run. If so, mixing in this trait into just those suites will allow their long-running tests to run in parallel with each other, thereby helping to reduce the total time required to run an entire run.

To make it easier for users to write tests that run in parallel, this trait runs each test in its own instance of the class. Running each test in its own instance enables tests to use the same instance vars and mutable objects referenced from instance variables without needing to synchronize. Although ScalaTest provides functional approaches to factoring out common test code that can help avoid such issues, running each test in its own instance is an insurance policy that makes running tests in parallel easier and less error prone.

For the details on how ParallelTestExecution works, see the documentation for methods run, runTests, and runTest, which this trait overrides.

Note: This trait's implementation of runTest is final, to ensure that behavior related to individual tests are executed by the same thread that executes the actual test. This means, for example, that you won't be allowed to write ...with ParallelTestExecution with BeforeAndAfter. Instead, you'd need to put ParallelTestExecution last, as in: with BeforeAndAfter with ParallelTestExecution. For more details, see the documentation for the runTest method.

class Object
trait Matchable
class Any

Value members

Concrete methods

Construct a new instance of this Suite.

Construct a new instance of this Suite.

This trait's implementation of runTests invokes this method to create a new instance of this Suite for each test. This trait's implementation of this method uses reflection to call this.getClass.newInstance. This approach will succeed only if this Suite's class has a public, no-arg constructor. In most cases this is likely to be true, because to be instantiated by ScalaTest's Runner a Suite needs a public, no-arg constructor. However, this will not be true of any Suite defined as an inner class of another class or trait, because every constructor of an inner class type takes a reference to the enclosing instance. In such cases, and in cases where a Suite class is explicitly defined without a public, no-arg constructor, you will need to override this method to construct a new instance of the Suite in some other way.

Here's an example of how you could override newInstance to construct a new instance of an inner class:

import org.scalatest.Suite

class Outer {
 class InnerSuite extends Suite with ParallelTestExecution {
   def testOne() {}
   def testTwo() {}
   override def newInstance = new InnerSuite
 }
}
Definition Classes
def run(testName: Option[String], args: Args): Status

Modifies the behavior of super.run to facilitate parallel test execution.

Modifies the behavior of super.run to facilitate parallel test execution.

This trait's implementation of this method only changes the supertrait implementation if both testName and args.distributedTestSorter are defined. If either testName or args.distributedTestSorter is empty, it simply invokes super.run, passing along the same testName and args object.

If both testName and args.distributedTestSorter are defined, however, this trait's implementation of this method will create a "test-specific reporter" whose apply method will invoke the apply method of the DistributedTestSorter, which takes a test name as well as the event. It will then invoke super.run passing along the same testName and an Args object that is the same except with the original reporter replaced by the test-specific reporter.

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.

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

Modifies the behavior of super.runTest to facilitate parallel test execution.

Modifies the behavior of super.runTest to facilitate parallel test execution.

This trait's implementation of this method only changes the supertrait implementation if args.distributor is defined. If args.distributor is empty, it simply invokes super.runTests, passing along the same testName and args object.

If args.distributor is defined, then it uses the args.runTestInNewInstance flag to decide what to do. If runTestInNewInstance is true, this is the general instance responsible for running all tests, so it first notifies args.distributedTestSorter (if defined) that it is distributing this test by invoking distributingTest on it, passing in the testName. Then it wraps a new instance of this class, obtained by invoking newInstance in a suite whose run method will ensure that only the test whose name was passed to this method as testName is executed. Finally, this trait's implementation of this method submits this wrapper suite to the distributor.

If runTestInNewInstance is false, this is the test-specific (distributed) instance, so this trait's implementation of this method simply invokes super.runTest, passing along the same testName and args object, delegating responsibility for actually running the test to the super implementation. After super.runTest returns (or completes abruptly by throwing an exception), it notifies args.distributedTestSorter (if defined) that it has completed running the test by invoking completedTest on it, passing in the testName.

Note: this trait's implementation of this method is final to ensure that any other desired runTest behavior is executed by the same thread that executes the test. For example, if you were to mix in BeforeAndAfter after ParallelTestExecution, the before and after code would be executed by the general instance on the main test thread, rather than by the test-specific instance on the distributed thread. Marking this method final ensures that traits like BeforeAndAfter can only be "super" to ParallelTestExecution and, therefore, that its before and after code will be run by the same distributed thread that runs the test itself.

Value parameters:
args

the Args for this run

testName

the name of one test to execute.

Returns:

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

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

Modifies the behavior of super.runTests to facilitate parallel test execution.

Modifies the behavior of super.runTests to facilitate parallel test execution.

This trait's implementation of this method always invokes super.runTests to delegate to OneInstancePerTest's implementation, but it may pass in a modified args object. If args.runTestInNewInstance is false and args.distributor is defined, this trait's implementation of this method will wrap the passed args.reporter in a new Reporter that can sort events fired by parallel tests back into sequential order, with a timeout. It will pass this new reporter to super.runTests (in args.reporter) as well as a defined DistributedTestSorter (in args.distributedTestSorter) that can be used to communicate with the sorting reporter. Otherwise, if args.runTestInNewInstance is true or args.distributor is empty, this trait's implementation of this method simply calls super.runTests, passing along the same testName and args.

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.

protected def sortingTimeout: Span

A maximum amount of time to wait for out-of-order events generated by running the tests of this Suite in parallel while sorting the events back into a more user-friendly, sequential order.

A maximum amount of time to wait for out-of-order events generated by running the tests of this Suite in parallel while sorting the events back into a more user-friendly, sequential order.

The default implementation of this method returns the value specified via -T to Runner, or 2 seconds, if no -T was supplied.

Returns:

a maximum amount of time to wait for events while resorting them into sequential order

Inherited methods

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.

Value parameters:
filter

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

Inherited from:
SuiteMixin
def nestedSuites: IndexedSeq[Suite]

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

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
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.

Inherited from:
SuiteMixin
protected 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.

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
def suiteId: String

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

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
def suiteName: String

A user-friendly suite name for this Suite.

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

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.

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
def testDataFor(testName: String, theConfigMap: ConfigMap): TestData

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

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
def testNames: Set[String]

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

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")
val styleName: String

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

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