OneInstancePerTest
Trait that facilitates a style of testing in which each test is run in its own instance of the suite class to isolate each test from the side effects of the other tests in the suite.
Recommended Usage: Trait OneInstancePerTest is intended primarily to serve as a supertrait for
ParallelTestExecution and the path traits, to
facilitate porting JUnit tests to ScalaTest, and to make it easy for users who prefer JUnit's approach to isolation to obtain similar
behavior in ScalaTest.
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If you mix this trait into a Suite, you can initialize shared reassignable
fixture variables as well as shared mutable fixture objects in the constructor of the
class. Because each test will run in its own instance of the class, each test will
get a fresh copy of the instance variables. This is the approach to test isolation taken,
for example, by the JUnit framework. OneInstancePerTest can, therefore,
be handy when porting JUnit tests to ScalaTest.
Here's an example of OneInstancePerTest being used in a FunSuite:
import org.scalatest.FunSuite
import org.scalatest.OneInstancePerTest
import collection.mutable.ListBuffer
class MySuite extends FunSuite with OneInstancePerTest {
val builder = new StringBuilder("ScalaTest is ")
val buffer = new ListBuffer[String]
test("easy") {
builder.append("easy!")
assert(builder.toString === "ScalaTest is easy!")
assert(buffer.isEmpty)
buffer += "sweet"
}
test("fun") {
builder.append("fun!")
assert(builder.toString === "ScalaTest is fun!")
assert(buffer.isEmpty)
}
}
OneInstancePerTest is supertrait to ParallelTestExecution, in which
running each test in its own instance is intended to make it easier to write suites of tests that run in parallel (by reducing the likelihood
of concurrency bugs in those suites.) OneInstancePerTest is also supertrait to the path traits,
path.FunSpec and path.FreeSpec, to make it obvious
these traits run each test in a new, isolated instance.
For the details on how OneInstancePerTest works, see the documentation for methods runTests and runTest,
which this trait overrides.
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 OneInstancePerTest {
def testOne() {}
def testTwo() {}
override def newInstance = new InnerSuite
}
}
Modifies the behavior of super.runTest to facilitate running each test in its
own instance of this Suite's class.
Modifies the behavior of super.runTest to facilitate running each test in its
own instance of this Suite's class.
This trait's implementation of runTest
uses the runTestInNewInstance flag of the passed Args object to determine whether this instance is the general instance responsible
for running all tests in the suite (runTestInNewInstance is true), or a test-specific instance
responsible for running just one test (runTestInNewInstance is false).
Note that these Boolean values are reverse those used by runTests, because runTests always inverts the Boolean value
of runTestInNewInstance when invoking runTest.
If runTestInNewInstance is true, this trait's implementation of this method creates a new instance of this class (by
invoking newInstance on itself), then invokes run on the new instance,
passing in testName, wrapped in a Some, and args unchanged.
(I.e., the Args object passed to runTest is forwarded as is to run
on the new instance, including with runTestInNewInstance set.)
If the invocation of either newInstance on this
Suite or run on a newly created instance of this Suite
completes abruptly with an exception, then this runTests method will complete
abruptly with the same exception.
If runTestInNewInstance is false, this trait's implementation of this method simply invokes super.runTest,
passing along the same testName and args objects.
- Value parameters:
- args
the
Argsfor this run- testName
the name of one test to execute.
- Returns:
a
Statusobject that indicates when the test started by this method has completed, and whether or not it failed .
Modifies the behavior of super.runTests to facilitate running each test in its
own instance of this Suite's class.
Modifies the behavior of super.runTests to facilitate running each test in its
own instance of this Suite's class.
This trait's implementation of runTest
uses the runTestInNewInstance flag of the passed Args object to determine whether this instance is the general instance responsible
for running all tests in the suite (runTestInNewInstance is false), or a test-specific instance
responsible for running just one test (runTestInNewInstance is true). Note that these Boolean values are
reverse those used by runTest, because runTests always inverts the Boolean value of
runTestInNewInstance when invoking runTest.
If runTestInNewInstance is false, this trait's implementation of this method will invoke
super.runTests, passing along testName and args, but with the
runTestInNewInstance flag set to true. By setting runTestInNewInstance to
true, runTests is telling runTest to create a new instance to run each test.
If runTestInNewInstance is true, this trait's implementation of this method will invoke
runTest directly, passing in testName.get and the args object, with
the runTestInNewInstance flag set to false. By setting runTestInNewInstance to
false, runTests is telling runTest that this is the test-specific instance,
so it should just run the specified test.
- Value parameters:
- args
the
Argsfor this run- testName
an optional name of one test to run. If
None, all relevant tests should be run. I.e.,Noneacts like a wildcard that means run all relevant tests in thisSuite.
- Returns:
a
Statusobject that indicates when all tests started by this method have completed, and whether or not a failure occurred.- Throws:
- IllegalArgumentException
if
testNameis defined, but no test with the specified test name exists in thisSuite, or ifrunTestInNewInstanceistrue, buttestNameis empty.- NullPointerException
if any of the passed parameters is
null.
Inherited methods
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
Filterwith 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.
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.
The fully qualified name of the class that can be used to rerun this suite.
- Inherited from:
- SuiteMixin
Runs this suite of tests.
Runs this suite of tests.
- Value parameters:
- args
the
Argsfor this run- testName
an optional name of one test to execute. If
None, all relevant tests should be executed. I.e.,Noneacts like a wildcard that means execute all relevant tests in thisSuite.
- Returns:
a
Statusobject 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.
Runs zero to many of this suite's nested suites.
- Value parameters:
- args
the
Argsfor this run
- Returns:
a
Statusobject that indicates when all nested suites started by this method have completed, and whether or not a failure occurred.- Throws:
- NullArgumentException
if
argsisnull.
- Inherited from:
- SuiteMixin
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
Suiteobject's ID.- Inherited from:
- SuiteMixin
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
Suiteobject'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.
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.
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
TestDatainstance- theConfigMap
the config map to include in the returned
TestData
- Returns:
a
TestDatainstance 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.
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
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