org.scalatest.fixture

FixtureFunSuite

trait FixtureFunSuite extends FixtureSuite

A sister trait to org.scalatest.FunSuite that can pass a fixture object into its tests.

This trait behaves similarly to trait org.scalatest.FunSuite, except that tests may take a fixture object. The type of the fixture object passed is defined by the abstract Fixture type, which is declared as a member of this trait (inherited from supertrait FixtureSuite). This trait also inherits the abstract method withFixture from supertrait FixtureSuite. The withFixture method takes a OneArgTest, which is a nested trait defined as a member of supertrait FixtureSuite. OneArgTest has an apply method that takes a Fixture. This apply method is responsible for running a test. This trait's runTest method delegates the actual running of each test to withFixture, passing in the test code to run via the OneArgTest argument. The withFixture method (abstract in this trait) is responsible for creating the fixture and passing it to the test function.

Subclasses of this trait must, therefore, do three things differently from a plain old org.scalatest.FunSuite:

  1. define the type of the fixture object by specifying type Fixture
  2. define the withFixture method
  3. write tests that take a Fixture (You can also define tests that don't take a Fixture.)

Here's an example:

import org.scalatest.fixture.FixtureFunSuite
import java.io.FileReader
import java.io.FileWriter
import java.io.File

class MyFunSuite extends FixtureFunSuite {

// 1. define type FixtureParam type FixtureParam = FileReader

// 2. define the withFixture method def withFixture(test: OneArgTest) {

val FileName = "TempFile.txt"

// Set up the temp file needed by the test val writer = new FileWriter(FileName) try { writer.write("Hello, test!") } finally { writer.close() }

// Create the reader needed by the test val reader = new FileReader(FileName)

try { // Run the test using the temp file test(reader) } finally { // Close and delete the temp file reader.close() val file = new File(FileName) file.delete() } }

// 3. write tests that take a fixture parameter test("reading from the temp file") { reader => var builder = new StringBuilder var c = reader.read() while (c != -1) { builder.append(c.toChar) c = reader.read() } assert(builder.toString === "Hello, test!") }

test("first char of the temp file") { reader => assert(reader.read() === 'H') }

// (You can also write tests that don't take a fixture parameter.) test("without a fixture") { () => assert(1 + 1 === 2) } }

If the fixture you want to pass into your tests consists of multiple objects, you will need to combine them into one object to use this trait. One good approach to passing multiple fixture objects is to encapsulate them in a tuple. Here's an example that takes the tuple approach:

import org.scalatest.fixture.FixtureFunSuite
import scala.collection.mutable.ListBuffer

class MyFunSuite extends FixtureFunSuite {

type FixtureParam = (StringBuilder, ListBuffer[String])

def withFixture(test: OneArgTest) {

// Create needed mutable objects val stringBuilder = new StringBuilder("ScalaTest is ") val listBuffer = new ListBuffer[String]

// Invoke the test function, passing in the mutable objects test(stringBuilder, listBuffer) }

test("easy") { fixture => val (builder, buffer) = fixture builder.append("easy!") assert(builder.toString === "ScalaTest is easy!") assert(buffer.isEmpty) buffer += "sweet" }

test("fun") { fixture => val (builder, buffer) = fixture builder.append("fun!") assert(builder.toString === "ScalaTest is fun!") assert(buffer.isEmpty) } }

When using a tuple to pass multiple fixture objects, it is usually helpful to give names to each individual object in the tuple with a pattern-match assignment, as is done at the beginning of each test here with:

val (builder, buffer) = fixture

Another good approach to passing multiple fixture objects is to encapsulate them in a case class. Here's an example that takes the case class approach:

import org.scalatest.fixture.FixtureFunSuite
import scala.collection.mutable.ListBuffer

class MyFunSuite extends FixtureFunSuite {

case class FixtureHolder(builder: StringBuilder, buffer: ListBuffer[String])

type FixtureParam = FixtureHolder

def withFixture(test: OneArgTest) {

// Create needed mutable objects val stringBuilder = new StringBuilder("ScalaTest is ") val listBuffer = new ListBuffer[String]

// Invoke the test function, passing in the mutable objects test(FixtureHolder(stringBuilder, listBuffer)) }

test("easy") { fixture => import fixture._ builder.append("easy!") assert(builder.toString === "ScalaTest is easy!") assert(buffer.isEmpty) buffer += "sweet" }

test("fun") { fixture => fixture.builder.append("fun!") assert(fixture.builder.toString === "ScalaTest is fun!") assert(fixture.buffer.isEmpty) } }

When using a case class to pass multiple fixture objects, it can be helpful to make the names of each individual object available as a single identifier with an import statement. This is the approach taken by the testEasy method in the previous example. Because it imports the members of the fixture object, the test code can just use them as unqualified identifiers:

test("easy") { fixture =>
  import fixture._
  builder.append("easy!")
  assert(builder.toString === "ScalaTest is easy!")
  assert(buffer.isEmpty)
  buffer += "sweet"
}

Alternatively, you may sometimes prefer to qualify each use of a fixture object with the name of the fixture parameter. This approach, taken by the testFun method in the previous example, makes it more obvious which variables in your test are part of the passed-in fixture:

test("fun") { fixture =>
  fixture.builder.append("fun!")
  assert(fixture.builder.toString === "ScalaTest is fun!")
  assert(fixture.buffer.isEmpty)
}

Configuring fixtures and tests

Sometimes you may want to write tests that are configurable. For example, you may want to write a suite of tests that each take an open temp file as a fixture, but whose file name is specified externally so that the file name can be can be changed from run to run. To accomplish this the OneArgTest trait has a configMap method, which will return a Map[String, Any] from which configuration information may be obtained. The runTest method of this trait will pass a OneArgTest to withFixture whose configMap method returns the configMap passed to runTest. Here's an example in which the name of a temp file is taken from the passed configMap:

import org.scalatest.fixture.FixtureFunSuite
import java.io.FileReader
import java.io.FileWriter
import java.io.File

class MyFunSuite extends FixtureFunSuite {

type FixtureParam = FileReader

def withFixture(test: OneArgTest) {

require( test.configMap.contains("TempFileName"), "This suite requires a TempFileName to be passed in the configMap" )

// Grab the file name from the configMap val FileName = test.configMap("TempFileName")

// Set up the temp file needed by the test val writer = new FileWriter(FileName) try { writer.write("Hello, test!") } finally { writer.close() }

// Create the reader needed by the test val reader = new FileReader(FileName)

try { // Run the test using the temp file test(reader) } finally { // Close and delete the temp file reader.close() val file = new File(FileName) file.delete() } }

test("reading from the temp file") { reader => var builder = new StringBuilder var c = reader.read() while (c != -1) { builder.append(c.toChar) c = reader.read() } assert(builder.toString === "Hello, test!") }

test("first char of the temp file") { reader => assert(reader.read() === 'H') } }

If you want to pass into each test the entire configMap that was passed to runTest, you can mix in trait ConfigMapFixture. See the documentation for ConfigMapFixture for the details, but here's a quick example of how it looks:

 import org.scalatest.fixture.FixtureFunSuite
 import org.scalatest.fixture.ConfigMapFixture

class MyFunSuite extends FixtureFunSuite with ConfigMapFixture {

test("hello") { configMap => // Use the configMap passed to runTest in the test assert(configMap.contains("hello") }

test("world") { configMap => assert(configMap.contains("world") } }

ConfigMapFixture can also be used to facilitate writing FixtureFunSuites that include tests that take different fixture types. See the documentation for MultipleFixtureFunSuite for more information.

known subclasses: MultipleFixtureFunSuite

Inherits

  1. FixtureSuite
  2. Suite
  3. AbstractSuite
  4. Assertions
  5. AnyRef
  6. Any

Type Members

  1. class Equalizer extends AnyRef

    Class used via an implicit conversion to enable any two objects to be compared with === in assertions in tests

Value Members

  1. def assert(o: Option[String]): Unit

    Assert that an Option[String] is None

    Assert that an Option[String] is None. If the condition is None, this method returns normally. Else, it throws TestFailedException with the String value of the Some included in the TestFailedException's detail message.

    This form of assert is usually called in conjunction with an implicit conversion to Equalizer, using a === comparison, as in:

    assert(a === b)
    

    For more information on how this mechanism works, see the documentation for Equalizer.

    o

    the Option[String] to assert

    definition classes: Assertions
  2. def assert(o: Option[String], clue: Any): Unit

    Assert that an Option[String] is None

    Assert that an Option[String] is None. If the condition is None, this method returns normally. Else, it throws TestFailedException with the String value of the Some, as well as the String obtained by invoking toString on the specified message, included in the TestFailedException's detail message.

    This form of assert is usually called in conjunction with an implicit conversion to Equalizer, using a === comparison, as in:

    assert(a === b, "extra info reported if assertion fails")
    

    For more information on how this mechanism works, see the documentation for Equalizer.

    o

    the Option[String] to assert

    clue

    An objects whose toString method returns a message to include in a failure report.

    definition classes: Assertions
  3. def assert(condition: Boolean, clue: Any): Unit

    Assert that a boolean condition, described in String message, is true

    Assert that a boolean condition, described in String message, is true. If the condition is true, this method returns normally. Else, it throws TestFailedException with the String obtained by invoking toString on the specified message as the exception's detail message.

    condition

    the boolean condition to assert

    clue

    An objects whose toString method returns a message to include in a failure report.

    definition classes: Assertions
  4. def assert(condition: Boolean): Unit

    Assert that a boolean condition is true

    Assert that a boolean condition is true. If the condition is true, this method returns normally. Else, it throws TestFailedException.

    condition

    the boolean condition to assert

    definition classes: Assertions
  5. def convertToEqualizer(left: Any): Equalizer

    Implicit conversion from Any to Equalizer, used to enable assertions with === comparisons

    Implicit conversion from Any to Equalizer, used to enable assertions with === comparisons.

    For more information on this mechanism, see the documentation for Equalizer.

    Because trait Suite mixes in Assertions, this implicit conversion will always be available by default in ScalaTest Suites. This is the only implicit conversion that is in scope by default in every ScalaTest Suite. Other implicit conversions offered by ScalaTest, such as those that support the matchers DSL or invokePrivate, must be explicitly invited into your test code, either by mixing in a trait or importing the members of its companion object. The reason ScalaTest requires you to invite in implicit conversions (with the exception of the implicit conversion for === operator) is because if one of ScalaTest's implicit conversions clashes with an implicit conversion used in the code you are trying to test, your program won't compile. Thus there is a chance that if you are ever trying to use a library or test some code that also offers an implicit conversion involving a === operator, you could run into the problem of a compiler error due to an ambiguous implicit conversion. If that happens, you can turn off the implicit conversion offered by this convertToEqualizer method simply by overriding the method in your Suite subclass, but not marking it as implicit:

    // In your Suite subclass
    override def convertToEqualizer(left: Any) = new Equalizer(left)
    

    left

    the object whose type to convert to Equalizer.

    attributes: implicit
    definition classes: Assertions
  6. def equals(arg0: Any): Boolean

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence

    This method is used to compare the receiver object (this) with the argument object (arg0) for equivalence.

    The default implementations of this method is an equivalence relation:

    • It is reflexive: for any instance x of type Any, x.equals(x) should return true.
    • It is symmetric: for any instances x and y of type Any, x.equals(y) should return true if and only if y.equals(x) returns true.
    • It is transitive: for any instances x, y, and z of type AnyRef if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.

    If you override this method, you should verify that your implementation remains an equivalence relation. Additionally, when overriding this method it is often necessary to override hashCode to ensure that objects that are "equal" (o1.equals(o2) returns true) hash to the same Int (o1.hashCode.equals(o2.hashCode)).

    arg0

    the object to compare against this object for equality.

    returns

    true if the receiver object is equivalent to the argument; false otherwise.

    definition classes: AnyRef ⇐ Any
  7. def expect(expected: Any)(actual: Any): Unit

    Expect that the value passed as expected equals the value passed as actual

    Expect that the value passed as expected equals the value passed as actual. If the actual value equals the expected value (as determined by ==), expect returns normally. Else, expect throws an TestFailedException whose detail message includes the expected and actual values.

    expected

    the expected value

    actual

    the actual value, which should equal the passed expected value

    definition classes: Assertions
  8. def expect(expected: Any, clue: Any)(actual: Any): Unit

    Expect that the value passed as expected equals the value passed as actual

    Expect that the value passed as expected equals the value passed as actual. If the actual equals the expected (as determined by ==), expect returns normally. Else, if actual is not equal to expected, expect throws an TestFailedException whose detail message includes the expected and actual values, as well as the String obtained by invoking toString on the passed message.

    expected

    the expected value

    clue

    An object whose toString method returns a message to include in a failure report.

    actual

    the actual value, which should equal the passed expected value

    definition classes: Assertions
  9. 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.

    This trait's implementation of this method returns the sum of:

    • the size of the testNames List, minus the number of tests marked as ignored
    • the sum of the values obtained by invoking expectedTestCount on every nested Suite contained in nestedSuites

    filter

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

    definition classes: SuiteAbstractSuite
  10. def fail(cause: Throwable): Nothing

    Throws TestFailedException, with the passed Throwable cause, to indicate a test failed

    Throws TestFailedException, with the passed Throwable cause, to indicate a test failed. The getMessage method of the thrown TestFailedException will return cause.toString().

    cause

    a Throwable that indicates the cause of the failure.

    definition classes: Assertions
  11. def fail(message: String, cause: Throwable): Nothing

    Throws TestFailedException, with the passed String message as the exception's detail message and Throwable cause, to indicate a test failed

    Throws TestFailedException, with the passed String message as the exception's detail message and Throwable cause, to indicate a test failed.

    message

    A message describing the failure.

    cause

    A Throwable that indicates the cause of the failure.

    definition classes: Assertions
  12. def fail(message: String): Nothing

    Throws TestFailedException, with the passed String message as the exception's detail message, to indicate a test failed

    Throws TestFailedException, with the passed String message as the exception's detail message, to indicate a test failed.

    message

    A message describing the failure.

    definition classes: Assertions
  13. def fail(): Nothing

    Throws TestFailedException to indicate a test failed

    Throws TestFailedException to indicate a test failed.

    definition classes: Assertions
  14. def hashCode(): Int

    Returns a hash code value for the object

    Returns a hash code value for the object.

    The default hashing algorithm is platform dependent.

    Note that it is allowed for two objects to have identical hash codes (o1.hashCode.equals(o2.hashCode)) yet not be equal (o1.equals(o2) returns false). A degenerate implementation could always return 0. However, it is required that if two objects are equal (o1.equals(o2) returns true) that they have identical hash codes (o1.hashCode.equals(o2.hashCode)). Therefore, when overriding this method, be sure to verify that the behavior is consistent with the equals method.

    definition classes: AnyRef ⇐ Any
  15. def intercept[T <: AnyRef](f: ⇒ Any)(manifest: Manifest[T]): T

    Intercept and return an exception that's expected to be thrown by the passed function value

    Intercept and return an exception that's expected to be thrown by the passed function value. The thrown exception must be an instance of the type specified by the type parameter of this method. This method invokes the passed function. If the function throws an exception that's an instance of the specified type, this method returns that exception. Else, whether the passed function returns normally or completes abruptly with a different exception, this method throws TestFailedException.

    Note that the type specified as this method's type parameter may represent any subtype of AnyRef, not just Throwable or one of its subclasses. In Scala, exceptions can be caught based on traits they implement, so it may at times make sense to specify a trait that the intercepted exception's class must mix in. If a class instance is passed for a type that could not possibly be used to catch an exception (such as String, for example), this method will complete abruptly with a TestFailedException.

    f

    the function value that should throw the expected exception

    manifest

    an implicit Manifest representing the type of the specified type parameter.

    returns

    the intercepted exception, if it is of the expected type

    definition classes: Assertions
  16. def nestedSuites: List[Suite]

    A List of this Suite object's nested Suites

    A List of this Suite object's nested Suites. If this Suite contains no nested Suites, this method returns an empty List. This trait's implementation of this method returns an empty List.

    definition classes: SuiteAbstractSuite
  17. def pending: PendingNothing

    Throws TestPendingException to indicate a test is pending

    Throws TestPendingException to indicate a test is pending.

    A pending test is one that has been given a name but is not yet implemented. The purpose of pending tests is to facilitate a style of testing in which documentation of behavior is sketched out before tests are written to verify that behavior (and often, the before the behavior of the system being tested is itself implemented). Such sketches form a kind of specification of what tests and functionality to implement later.

    To support this style of testing, a test can be given a name that specifies one bit of behavior required by the system being tested. The test can also include some code that sends more information about the behavior to the reporter when the tests run. At the end of the test, it can call method pending, which will cause it to complete abruptly with TestPendingException. Because tests in ScalaTest can be designated as pending with TestPendingException, both the test name and any information sent to the reporter when running the test can appear in the report of a test run. (In other words, the code of a pending test is executed just like any other test.) However, because the test completes abruptly with TestPendingException, the test will be reported as pending, to indicate the actual test, and possibly the functionality it is intended to test, has not yet been implemented.

    Note: This method always completes abruptly with a TestPendingException. Thus it always has a side effect. Methods with side effects are usually invoked with parentheses, as in pending(). This method is defined as a parameterless method, in flagrant contradiction to recommended Scala style, because it forms a kind of DSL for pending tests. It enables tests in suites such as FunSuite or Spec to be denoted by placing "(pending)" after the test name, as in:

    test("that style rules are not laws") (pending)
    

    Readers of the code see "pending" in parentheses, which looks like a little note attached to the test name to indicate it is pending. Whereas "(pending()) looks more like a method call, "(pending)" lets readers stay at a higher level, forgetting how it is implemented and just focusing on the intent of the programmer who wrote the code.

    definition classes: Suite
  18. def pendingUntilFixed(f: ⇒ Unit): Unit

    Execute the passed block of code, and if it completes abruptly, throw TestPendingException, else throw TestFailedException

    Execute the passed block of code, and if it completes abruptly, throw TestPendingException, else throw TestFailedException.

    This method can be used to temporarily change a failing test into a pending test in such a way that it will automatically turn back into a failing test once the problem originally causing the test to fail has been fixed. At that point, you need only remove the pendingUntilFixed call. In other words, a pendingUntilFixed surrounding a block of code that isn't broken is treated as a test failure. The motivation for this behavior is to encourage people to remove pendingUntilFixed calls when there are no longer needed.

    This method facilitates a style of testing in which tests are written before the code they test. Sometimes you may encounter a test failure that requires more functionality than you want to tackle without writing more tests. In this case you can mark the bit of test code causing the failure with pendingUntilFixed. You can then write more tests and functionality that eventually will get your production code to a point where the original test won't fail anymore. At this point the code block marked with pendingUntilFixed will no longer throw an exception (because the problem has been fixed). This will in turn cause pendingUntilFixed to throw TestFailedException with a detail message explaining you need to go back and remove the pendingUntilFixed call as the problem orginally causing your test code to fail has been fixed.

    f

    a block of code, which if it completes abruptly, should trigger a TestPendingException

    definition classes: Suite
  19. def run(testName: Option[String], reporter: Reporter, stopper: Stopper, filter: Filter, configMap: Map[String, Any], distributor: Option[Distributor], tracker: Tracker): Unit

    Runs this suite of tests

    Runs this suite of tests.

    If testName is None, this trait's implementation of this method calls these two methods on this object in this order:

    1. runNestedSuites(report, stopper, tagsToInclude, tagsToExclude, configMap, distributor)
    2. runTests(testName, report, stopper, tagsToInclude, tagsToExclude, configMap)

    If testName is defined, then this trait's implementation of this method calls runTests, but does not call runNestedSuites. This behavior is part of the contract of this method. Subclasses that override run must take care not to call runNestedSuites if testName is defined. (The OneInstancePerTest trait depends on this behavior, for example.)

    Subclasses and subtraits that override this run method can implement them without invoking either the runTests or runNestedSuites methods, which are invoked by this trait's implementation of this method. It is recommended, but not required, that subclasses and subtraits that override run in a way that does not invoke runNestedSuites also override runNestedSuites and make it final. Similarly it is recommended, but not required, that subclasses and subtraits that override run in a way that does not invoke runTests also override runTests (and runTest, which this trait's implementation of runTests calls) and make it final. The implementation of these final methods can either invoke the superclass implementation of the method, or throw an UnsupportedOperationException if appropriate. The reason for this recommendation is that ScalaTest includes several traits that override these methods to allow behavior to be mixed into a Suite. For example, trait BeforeAndAfterEach overrides runTestss. In a Suite subclass that no longer invokes runTests from run, the BeforeAndAfterEach trait is not applicable. Mixing it in would have no effect. By making runTests final in such a Suite subtrait, you make the attempt to mix BeforeAndAfterEach into a subclass of your subtrait a compiler error. (It would fail to compile with a complaint that BeforeAndAfterEach is trying to override runTests, which is a final method in your trait.)

    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.

    reporter

    the Reporter to which results will be reported

    stopper

    the Stopper that will be consulted to determine whether to stop execution early.

    filter

    a Filter with which to filter tests based on their tags

    configMap

    a Map of key-value pairs that can be used by the executing Suite of tests.

    distributor

    an optional Distributor, into which to put nested Suites to be run by another entity, such as concurrently by a pool of threads. If None, nested Suites will be run sequentially.

    tracker

    a Tracker tracking Ordinals being fired by the current thread.

  20. 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.

    definition classes: Suite
  21. def tags: Map[String, Set[String]]

    A Map whose keys are String tag names to which tests in this FunSuite belong, and values the Set of test names that belong to each tag

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

    This trait's implementation returns tags that were passed as strings contained in Tag objects passed to methods test and ignore.

  22. def testNames: Set[String]

    An immutable Set of test names

    An immutable Set of test names. If this FixtureFunSuite contains no tests, this method returns an empty Set.

    This trait's implementation of this method will return a set that contains the names of all registered tests. The set's iterator will return those names in the order in which the tests were registered.

  23. def toString(): String

    Returns a string representation of the object

    Returns a string representation of the object.

    The default representation is platform dependent.

    definition classes: AnyRef ⇐ Any