Check a property
Check a property.
the property to check
Check a property with the given testing parameters
Check a property with the given testing parameters.
the property to check
the test parameters
Convert the passed 6-arg function into a property, and check it
Convert the passed 6-arg function into a property, and check it.
the function to be converted into a property and checked
Convert the passed 5-arg function into a property, and check it
Convert the passed 5-arg function into a property, and check it.
the function to be converted into a property and checked
Convert the passed 4-arg function into a property, and check it
Convert the passed 4-arg function into a property, and check it.
the function to be converted into a property and checked
Convert the passed 3-arg function into a property, and check it
Convert the passed 3-arg function into a property, and check it.
the function to be converted into a property and checked
Convert the passed 2-arg function into a property, and check it
Convert the passed 2-arg function into a property, and check it.
the function to be converted into a property and checked
Convert the passed 1-arg function into a property, and check it
Convert the passed 1-arg function into a property, and check it.
the function to be converted into a property and checked
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:
x
of type Any
,
x.equals(x)
should return true
.x
and y
of type
Any
, x.equals(y)
should return true
if and only
if y.equals(x)
returns true
.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)
).
the object to compare against this object for equality.
true
if the receiver object is equivalent to the argument; false
otherwise.
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 a string representation of the object
Returns a string representation of the object.
The default representation is platform dependent.
Trait that contains several “check” methods that perform ScalaCheck property checks. If ScalaCheck finds a test case for which a property doesn't hold, the problem will be reported as a ScalaTest test failure.
To use ScalaCheck, you specify properties and, in some cases, generators that generate test data. You need not always create generators, because ScalaCheck provides many default generators for you that can be used in many situations. ScalaCheck will use the generators to generate test data and with that data run tests that check that the property holds. Property-based tests can, therefore, give you a lot more testing for a lot less code than assertion-based tests. Here's an example of using ScalaCheck from a
JUnitSuite
:The
check
method, defined inCheckers
, makes it easy to write property-based tests inside ScalaTest, JUnit, and TestNG test suites. This example specifies a property thatList
's:::
method should obey. ScalaCheck properties are expressed as function values that take the required test data as parameters. ScalaCheck will generate test data using generators and repeatedly pass generated data to the function. In this case, the test data is composed of integer lists nameda
andb
. Inside the body of the function, you see:The property in this case is a
Boolean
expression that will yield true if the size of the concatenated list is equal to the size of each individual list added together. With this small amount of code, ScalaCheck will generate possibly hundreds of value pairs fora
andb
and test each pair, looking for a pair of integers for which the property doesn't hold. If the property holds true for every value ScalaCheck tries,check
returns normally. Otherwise,check
will complete abruptly with aTestFailedException
that contains information about the failure, including the values that cause the property to be false.For more information on using ScalaCheck properties, see the documentation for ScalaCheck, which is available from http://code.google.com/p/scalacheck/.
To execute a suite that mixes in
Checkers
with ScalaTest'sRunner
, you must include ScalaCheck's jar file on the class path or runpath. This version ofCheckers
was tested with ScalaCheck version 1.1.1. This trait must be mixed into a ScalaTestSuite
, because its self type isorg.scalatest.Suite
.