org.scalatest.junit

# AssertionsForJUnit

#### trait AssertionsForJUnit extends Assertions

Trait that contains ScalaTest's basic assertion methods, suitable for use with JUnit.

The assertion methods provided in this trait look and behave exactly like the ones in `Assertions`, except instead of throwing `TestFailedException` they throw `JUnitTestFailedError`, which extends `junit.framework.AssertionFailedError`.

JUnit 3 (release 3.8 and earlier) distinguishes between failures and errors. If a test fails because of a failed assertion, that is considered a failure. If a test fails for any other reason, either the test code or the application being tested threw an unexpected exception, that is considered an error. The way JUnit 3 decides whether an exception represents a failure or error is that only thrown `junit.framework.AssertionFailedError`s are considered failures. Any other exception type is considered an error. The exception type thrown by the JUnit 3 assertion methods declared in `junit.framework.Assert` (such as `assertEquals`, `assertTrue`, and `fail`) is, therefore, `AssertionFailedError`.

In JUnit 4, `AssertionFailedError` was made to extend `java.lang.AssertionError`, and the distinction between failures and errors was essentially dropped. However, some tools that integrate with JUnit carry on this distinction, so even if you are using JUnit 4 you may want to use this `AssertionsForJUnit` trait instead of plain-old ScalaTest `Assertions`.

To use this trait in a JUnit 3 `TestCase`, you can mix it into your `TestCase` class, like this:

    import junit.framework.TestCase
    import org.scalatest.junit.AssertionsForJUnit

    class MyTestCase extends TestCase with AssertionsForJUnit {

      def testSomething() {
        assert("hi".charAt(1) === 'i')
      }

      // ...
    }

You can alternatively import the methods defined in this trait.

    import junit.framework.TestCase
    import org.scalatest.junit.AssertionsForJUnit._

    class MyTestCase extends TestCase {

      def testSomething() {
        assert("hi".charAt(1) === 'i')
      }

      // ...
    }

For details on the importing approach, see the documentation for the `AssertionsForJUnit` companion object. For the details on the `AssertionsForJUnit` syntax, see the Scaladoc documentation for `org.scalatest.Assertions`

Linear Supertypes
Assertions, AnyRef, Any
Known Subclasses
AssertionsForJUnit, JUnit3Suite, JUnitSuite, MustMatchersForJUnit, MustMatchersForJUnit, ShouldMatchersForJUnit, ShouldMatchersForJUnit
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1. AssertionsForJUnit
2. Assertions
3. AnyRef
4. Any

Visibility

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### 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 != (arg0: AnyRef): Boolean

   Attributes
     final
   Definition Classes
     AnyRef

2. #### def != (arg0: Any): Boolean

   Attributes
     final
   Definition Classes
     Any

3. #### def ## (): Int

   Attributes
     final
   Definition Classes
     AnyRef → Any

4. #### def == (arg0: AnyRef): Boolean

   Attributes
     final
   Definition Classes
     AnyRef

5. #### def == (arg0: Any): Boolean

   Attributes
     final
   Definition Classes
     Any

6. #### def asInstanceOf [T0] : T0

   Attributes
     final
   Definition Classes
     Any

7. #### 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

8. #### 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

9. #### 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

10. #### 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

11. #### def clone (): AnyRef

    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws()

12. #### implicit 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 `Suite`s. 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

13. #### def eq (arg0: AnyRef): Boolean

    Attributes
      final
    Definition Classes
      AnyRef

14. #### def equals (arg0: Any): Boolean

    Definition Classes
      AnyRef → Any

15. #### 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

16. #### 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

17. #### 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

18. #### 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

19. #### 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

20. #### def fail (): Nothing

    Throws `TestFailedException` to indicate a test failed.

    Throws `TestFailedException` to indicate a test failed.

    Definition Classes
      Assertions

21. #### def finalize (): Unit

    Attributes
      protected[lang]
    Definition Classes
      AnyRef
    Annotations
      @throws()

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

    Attributes
      final
    Definition Classes
      AnyRef

23. #### def hashCode (): Int

    Definition Classes
      AnyRef → Any

24. #### def intercept [T <: AnyRef] (f: ⇒ Any)(implicit 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

25. #### def isInstanceOf [T0] : Boolean

    Attributes
      final
    Definition Classes
      Any

26. #### def ne (arg0: AnyRef): Boolean

    Attributes
      final
    Definition Classes
      AnyRef

27. #### def notify (): Unit

    Attributes
      final
    Definition Classes
      AnyRef

28. #### def notifyAll (): Unit

    Attributes
      final
    Definition Classes
      AnyRef

29. #### def synchronized [T0] (arg0: ⇒ T0): T0

    Attributes
      final
    Definition Classes
      AnyRef

30. #### def toString (): String

    Definition Classes
      AnyRef → Any

31. #### def wait (): Unit

    Attributes
      final
    Definition Classes
      AnyRef
    Annotations
      @throws()

32. #### def wait (arg0: Long, arg1: Int): Unit

    Attributes
      final
    Definition Classes
      AnyRef
    Annotations
      @throws()

33. #### def wait (arg0: Long): Unit

    Attributes
      final
    Definition Classes
      AnyRef
    Annotations
      @throws()

34. #### def withClue (clue: Any)(fun: ⇒ Unit): Unit

    Executes the block of code passed as the second parameter, and, if it completes abruptly with a `ModifiableMessage` exception, prepends the "clue" string passed as the first parameter to the beginning of the detail message of that thrown exception, then rethrows it.

    Executes the block of code passed as the second parameter, and, if it completes abruptly with a `ModifiableMessage` exception, prepends the "clue" string passed as the first parameter to the beginning of the detail message of that thrown exception, then rethrows it. If clue does not end in a white space character, one space will be added between it and the existing detail message (unless the detail message is not defined).

    This method allows you to add more information about what went wrong that will be reported when a test fails. Here's an example:

        withClue("(Employee's name was: " + employee.name + ")") {
          intercept[IllegalArgumentException] {
            employee.getTask(-1)
          }
        }

    If an invocation of `intercept` completed abruptly with an exception, the resulting message would be something like:

        (Employee's name was Bob Jones) Expected IllegalArgumentException to be thrown, but no exception was thrown

    Definition Classes
      Assertions

### Inherited from Assertions

### Inherited from AnyRef

### Inherited from Any