org.scalatest.matchers

BePropertyMatcher

trait BePropertyMatcher[-T] extends (T) ⇒ BePropertyMatchResult

Trait extended by matcher objects, which may appear after the word be, that can match against a Booleanproperty. The match will succeed if and only if the Boolean property equals true. The object containing the property, which must be of the type specified by the BePropertyMatcher's type parameter T, is passed to the BePropertyMatcher'sapply method. The result is a BePropertyMatchResult. A BePropertyMatcher is, therefore, a function from the specified type, T, to a BePropertyMatchResult.

Although BePropertyMatcherand Matcher represent similar concepts, they have no inheritance relationship because Matcher is intended for use right after should or mustwhereas BePropertyMatcher is intended for use right after be.

A BePropertyMatcher essentially allows you to write statically typed Booleanproperty assertions similar to the dynamic ones that use symbols:

tempFile should be a ('file) // dynamic: uses reflection
tempFile should be a (file)  // type safe: only works on Files; no reflection used

One good way to organize custom matchers is to place them inside one or more traits that you can then mix into the suites or specs that need them. Here's an example that includes two BePropertyMatchers:

trait CustomMatchers {

class FileBePropertyMatcher extends BePropertyMatcher[java.io.File] { def apply(left: java.io.File) = BePropertyMatchResult(left.isFile, "file") }

class DirectoryBePropertyMatcher extends BePropertyMatcher[java.io.File] { def apply(left: java.io.File) = BePropertyMatchResult(left.isDirectory, "directory") }

val file = new FileBePropertyMatcher val directory = new DirectoryBePropertyMatcher }

Because the type parameter of these two BePropertyMatchers is java.io.File, they can only be used with instances of that type. (The compiler will enforce this.) All they do is create aBePropertyMatchResult whose matches field is true if and only if the Boolean property is true. The second field, propertyName, is simply the string name of the property. The file and directory vals create variables that can be used in matcher expressions that test whether a java.io.File is a file or a directory. Here's an example:

class ExampleSpec extends Spec with ShouldMatchers with CustomMatchers {

describe("A temp file") {

it("should be a file, not a directory") {

val tempFile = java.io.File.createTempFile("delete", "me")

try { tempFile should be a (file) tempFile should not be a (directory) } finally { tempFile.delete() } } } }

These matches should succeed, but if for example the first match, tempFile should be a (file), were to fail, you would get an error message like:

/tmp/delme1234me was not a file

For more information on BePropertyMatchResult and the meaning of its fields, please see the documentation for BePropertyMatchResult. To understand why BePropertyMatcheris contravariant in its type parameter, see the section entitled "Matcher's variance" in the documentation for Matcher.

    authors:
  1. Bill Venners

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Value Members

  1. def !=(arg0: AnyRef): Boolean

    attributes: final
    definition classes: AnyRef
  2. def !=(arg0: Any): Boolean

    o != arg0 is the same as !(o == (arg0)).

    o != arg0 is the same as !(o == (arg0)).

    arg0

    the object to compare against this object for dis-equality.

    returns

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

    attributes: final
    definition classes: Any
  3. def ##(): Int

    attributes: final
    definition classes: AnyRef → Any
  4. def $asInstanceOf[T0](): T0

    attributes: final
    definition classes: AnyRef
  5. def $isInstanceOf[T0](): Boolean

    attributes: final
    definition classes: AnyRef
  6. def ==(arg0: AnyRef): Boolean

    o == arg0 is the same as if (o eq null) arg0 eq null else o.equals(arg0).

    o == arg0 is the same as if (o eq null) arg0 eq null else o.equals(arg0).

    arg0

    the object to compare against this object for equality.

    returns

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

    attributes: final
    definition classes: AnyRef
  7. def ==(arg0: Any): Boolean

    o == arg0 is the same as o.equals(arg0).

    o == arg0 is the same as o.equals(arg0).

    arg0

    the object to compare against this object for equality.

    returns

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

    attributes: final
    definition classes: Any
  8. def andThen[A](g: (BePropertyMatchResult) ⇒ A): (T) ⇒ A

    definition classes: Function1
  9. def apply(objectWithProperty: T): BePropertyMatchResult

    Check to see if a Boolean property on the specified object, objectWithProperty, matches its expected value, and report the result in the returned BePropertyMatchResult.

    Check to see if a Boolean property on the specified object, objectWithProperty, matches its expected value, and report the result in the returned BePropertyMatchResult. The objectWithProperty is usually the value to the left of a should or must invocation. For example, tempFilewould be passed as the objectWithProperty in:

    tempFile should be a (file)

    objectWithProperty

    the object with the Boolean property against which to match

    returns

    the BePropertyMatchResult that represents the result of the match

    attributes: abstract
    definition classes: BePropertyMatcher → Function1
  10. def asInstanceOf[T0]: T0

    This method is used to cast the receiver object to be of type T0.

    This method is used to cast the receiver object to be of type T0.

    Note that the success of a cast at runtime is modulo Scala's erasure semantics. Therefore the expression1.asInstanceOf[String] will throw a ClassCastException at runtime, while the expressionList(1).asInstanceOf[List[String]] will not. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

    returns

    the receiver object.

    attributes: final
    definition classes: Any
  11. def clone(): AnyRef

    This method creates and returns a copy of the receiver object.

    This method creates and returns a copy of the receiver object.

    The default implementation of the clone method is platform dependent.

    returns

    a copy of the receiver object.

    attributes: protected
    definition classes: AnyRef
  12. def compose[A](g: (A) ⇒ T): (A) ⇒ BePropertyMatchResult

    definition classes: Function1
  13. def eq(arg0: AnyRef): Boolean

    This method is used to test whether the argument (arg0) is a reference to the receiver object (this).

    This method is used to test whether the argument (arg0) is a reference to the receiver object (this).

    The eq method implements an [http://en.wikipedia.org/wiki/Equivalence_relation equivalence relation] on non-null instances of AnyRef: * It is reflexive: for any non-null instance x of type AnyRef, x.eq(x) returns true. * It is symmetric: for any non-null instances x and y of type AnyRef, x.eq(y) returns true if and only if y.eq(x) returns true. * It is transitive: for any non-null instances x, y, and z of type AnyRef if x.eq(y) returns true and y.eq(z) returns true, then x.eq(z) returns true.

    Additionally, the eq method has three other properties. * It is consistent: for any non-null instances x and y of type AnyRef, multiple invocations of x.eq(y) consistently returns true or consistently returns false. * For any non-null instance x of type AnyRef, x.eq(null) and null.eq(x) returns false. * null.eq(null) returns true.

    When overriding the equals or hashCode methods, it is important to ensure that their behavior is consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).

    arg0

    the object to compare against this object for reference equality.

    returns

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

    attributes: final
    definition classes: AnyRef
  14. 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 [http://en.wikipedia.org/wiki/Equivalence_relation 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 scala.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
  15. def finalize(): Unit

    This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

    This method is called by the garbage collector on the receiver object when garbage collection determines that there are no more references to the object.

    The details of when and if the finalize method are invoked, as well as the interaction between finalizeand non-local returns and exceptions, are all platform dependent.

    attributes: protected
    definition classes: AnyRef
  16. def getClass(): java.lang.Class[_]

    Returns a representation that corresponds to the dynamic class of the receiver object.

    Returns a representation that corresponds to the dynamic class of the receiver object.

    The nature of the representation is platform dependent.

    returns

    a representation that corresponds to the dynamic class of the receiver object.

    attributes: final
    definition classes: AnyRef
  17. 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.

    returns

    the hash code value for the object.

    definition classes: AnyRef → Any
  18. def isInstanceOf[T0]: Boolean

    This method is used to test whether the dynamic type of the receiver object is T0.

    This method is used to test whether the dynamic type of the receiver object is T0.

    Note that the test result of the test is modulo Scala's erasure semantics. Therefore the expression1.isInstanceOf[String] will return false, while the expression List(1).isInstanceOf[List[String]] will return true. In the latter example, because the type argument is erased as part of compilation it is not possible to check whether the contents of the list are of the requested typed.

    returns

    true if the receiver object is an instance of erasure of type T0; false otherwise.

    attributes: final
    definition classes: Any
  19. def ne(arg0: AnyRef): Boolean

    o.ne(arg0) is the same as !(o.eq(arg0)).

    o.ne(arg0) is the same as !(o.eq(arg0)).

    arg0

    the object to compare against this object for reference dis-equality.

    returns

    false if the argument is not a reference to the receiver object; true otherwise.

    attributes: final
    definition classes: AnyRef
  20. def notify(): Unit

    Wakes up a single thread that is waiting on the receiver object's monitor.

    Wakes up a single thread that is waiting on the receiver object's monitor.

    attributes: final
    definition classes: AnyRef
  21. def notifyAll(): Unit

    Wakes up all threads that are waiting on the receiver object's monitor.

    Wakes up all threads that are waiting on the receiver object's monitor.

    attributes: final
    definition classes: AnyRef
  22. def synchronized[T0](arg0: T0): T0

    attributes: final
    definition classes: AnyRef
  23. def toString(): String

    Returns a string representation of the object.

    Returns a string representation of the object.

    The default representation is platform dependent.

    returns

    a string representation of the object.

    definition classes: Function1 → AnyRef → Any
  24. def wait(): Unit

    attributes: final
    definition classes: AnyRef
  25. def wait(arg0: Long, arg1: Int): Unit

    attributes: final
    definition classes: AnyRef
  26. def wait(arg0: Long): Unit

    attributes: final
    definition classes: AnyRef