ScalaTest 1.0
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org/scalatest/prop/Checkers.scala
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trait
Checkers
extends
AnyRef
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
:
import org.scalatest.junit.JUnitSuite import org.scalatest.prop.Checkers import org.scalacheck.Arbitrary._ import org.scalacheck.Prop._ class MySuite extends JUnitSuite with Checkers { @Test def testConcat() { check((a: List[Int], b: List[Int]) => a.size + b.size == (a ::: b).size) } }
The check
method, defined in Checkers
, makes it easy to write property-based tests inside
ScalaTest, JUnit, and TestNG test suites. This example specifies a property that List
'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 named a
and b
.
Inside the body of the function, you see:
a.size + b.size == (a ::: b).size
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 for a
and b
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 a TestFailedException
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's Runner
, you must include ScalaCheck's jar file on the class path or runpath.
This version of Checkers
was tested with ScalaCheck version 1.1.1. This trait must
be mixed into a ScalaTest Suite
, because its self type is org.scalatest.Suite
.
Method Summary | |
def
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check
[A1, A2, A3, A4, A5, P](f : (A1, A2, A3, A4, A5) => P)(implicit p : (P) => org.scalacheck.Prop, implicit a1 : org.scalacheck.Arbitrary[A1], implicit s1 : org.scalacheck.Shrink[A1], implicit a2 : org.scalacheck.Arbitrary[A2], implicit s2 : org.scalacheck.Shrink[A2], implicit a3 : org.scalacheck.Arbitrary[A3], implicit s3 : org.scalacheck.Shrink[A3], implicit a4 : org.scalacheck.Arbitrary[A4], implicit s4 : org.scalacheck.Shrink[A4], implicit a5 : org.scalacheck.Arbitrary[A5], implicit s5 : org.scalacheck.Shrink[A5]) : Unit
Convert the passed 5-arg function into a property, and check it.
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def
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check
[A1, A2, A3, A4, P](f : (A1, A2, A3, A4) => P)(implicit p : (P) => org.scalacheck.Prop, implicit a1 : org.scalacheck.Arbitrary[A1], implicit s1 : org.scalacheck.Shrink[A1], implicit a2 : org.scalacheck.Arbitrary[A2], implicit s2 : org.scalacheck.Shrink[A2], implicit a3 : org.scalacheck.Arbitrary[A3], implicit s3 : org.scalacheck.Shrink[A3], implicit a4 : org.scalacheck.Arbitrary[A4], implicit s4 : org.scalacheck.Shrink[A4]) : Unit
Convert the passed 4-arg function into a property, and check it.
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def
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check
[A1, P](f : (A1) => P)(implicit p : (P) => org.scalacheck.Prop, implicit a1 : org.scalacheck.Arbitrary[A1], implicit s1 : org.scalacheck.Shrink[A1]) : Unit
Convert the passed 1-arg function into a property, and check it.
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def
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check
(p : org.scalacheck.Prop) : Unit
Check a property.
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def
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check
(p : org.scalacheck.Prop, prms : org.scalacheck.Test.Params) : Unit
Check a property with the given testing parameters.
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def
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check
[A1, A2, A3, A4, A5, A6, P](f : (A1, A2, A3, A4, A5, A6) => P)(implicit p : (P) => org.scalacheck.Prop, implicit a1 : org.scalacheck.Arbitrary[A1], implicit s1 : org.scalacheck.Shrink[A1], implicit a2 : org.scalacheck.Arbitrary[A2], implicit s2 : org.scalacheck.Shrink[A2], implicit a3 : org.scalacheck.Arbitrary[A3], implicit s3 : org.scalacheck.Shrink[A3], implicit a4 : org.scalacheck.Arbitrary[A4], implicit s4 : org.scalacheck.Shrink[A4], implicit a5 : org.scalacheck.Arbitrary[A5], implicit s5 : org.scalacheck.Shrink[A5], implicit a6 : org.scalacheck.Arbitrary[A6], implicit s6 : org.scalacheck.Shrink[A6]) : Unit
Convert the passed 6-arg function into a property, and check it.
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def
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check
[A1, A2, P](f : (A1, A2) => P)(implicit p : (P) => org.scalacheck.Prop, implicit a1 : org.scalacheck.Arbitrary[A1], implicit s1 : org.scalacheck.Shrink[A1], implicit a2 : org.scalacheck.Arbitrary[A2], implicit s2 : org.scalacheck.Shrink[A2]) : Unit
Convert the passed 2-arg function into a property, and check it.
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def
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check
[A1, A2, A3, P](f : (A1, A2, A3) => P)(implicit p : (P) => org.scalacheck.Prop, implicit a1 : org.scalacheck.Arbitrary[A1], implicit s1 : org.scalacheck.Shrink[A1], implicit a2 : org.scalacheck.Arbitrary[A2], implicit s2 : org.scalacheck.Shrink[A2], implicit a3 : org.scalacheck.Arbitrary[A3], implicit s3 : org.scalacheck.Shrink[A3]) : Unit
Convert the passed 3-arg function into a property, and check it.
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Methods inherited from AnyRef | |
getClass, hashCode, equals, clone, toString, notify, notifyAll, wait, wait, wait, finalize, ==, !=, eq, ne, synchronized |
Methods inherited from Any | |
==, !=, isInstanceOf, asInstanceOf |
Method Details |
def
check[A1, P](f : (A1) => P)(implicit
p : (P) => org.scalacheck.Prop, implicit
a1 : org.scalacheck.Arbitrary[A1], implicit
s1 : org.scalacheck.Shrink[A1]) : Unit
f -
the function to be converted into a property and checkedTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check[A1, A2, P](f : (A1, A2) => P)(implicit
p : (P) => org.scalacheck.Prop, implicit
a1 : org.scalacheck.Arbitrary[A1], implicit
s1 : org.scalacheck.Shrink[A1], implicit
a2 : org.scalacheck.Arbitrary[A2], implicit
s2 : org.scalacheck.Shrink[A2]) : Unit
f -
the function to be converted into a property and checkedTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check[A1, A2, A3, P](f : (A1, A2, A3) => P)(implicit
p : (P) => org.scalacheck.Prop, implicit
a1 : org.scalacheck.Arbitrary[A1], implicit
s1 : org.scalacheck.Shrink[A1], implicit
a2 : org.scalacheck.Arbitrary[A2], implicit
s2 : org.scalacheck.Shrink[A2], implicit
a3 : org.scalacheck.Arbitrary[A3], implicit
s3 : org.scalacheck.Shrink[A3]) : Unit
f -
the function to be converted into a property and checkedTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check[A1, A2, A3, A4, P](f : (A1, A2, A3, A4) => P)(implicit
p : (P) => org.scalacheck.Prop, implicit
a1 : org.scalacheck.Arbitrary[A1], implicit
s1 : org.scalacheck.Shrink[A1], implicit
a2 : org.scalacheck.Arbitrary[A2], implicit
s2 : org.scalacheck.Shrink[A2], implicit
a3 : org.scalacheck.Arbitrary[A3], implicit
s3 : org.scalacheck.Shrink[A3], implicit
a4 : org.scalacheck.Arbitrary[A4], implicit
s4 : org.scalacheck.Shrink[A4]) : Unit
f -
the function to be converted into a property and checkedTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check[A1, A2, A3, A4, A5, P](f : (A1, A2, A3, A4, A5) => P)(implicit
p : (P) => org.scalacheck.Prop, implicit
a1 : org.scalacheck.Arbitrary[A1], implicit
s1 : org.scalacheck.Shrink[A1], implicit
a2 : org.scalacheck.Arbitrary[A2], implicit
s2 : org.scalacheck.Shrink[A2], implicit
a3 : org.scalacheck.Arbitrary[A3], implicit
s3 : org.scalacheck.Shrink[A3], implicit
a4 : org.scalacheck.Arbitrary[A4], implicit
s4 : org.scalacheck.Shrink[A4], implicit
a5 : org.scalacheck.Arbitrary[A5], implicit
s5 : org.scalacheck.Shrink[A5]) : Unit
f -
the function to be converted into a property and checkedTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check[A1, A2, A3, A4, A5, A6, P](f : (A1, A2, A3, A4, A5, A6) => P)(implicit
p : (P) => org.scalacheck.Prop, implicit
a1 : org.scalacheck.Arbitrary[A1], implicit
s1 : org.scalacheck.Shrink[A1], implicit
a2 : org.scalacheck.Arbitrary[A2], implicit
s2 : org.scalacheck.Shrink[A2], implicit
a3 : org.scalacheck.Arbitrary[A3], implicit
s3 : org.scalacheck.Shrink[A3], implicit
a4 : org.scalacheck.Arbitrary[A4], implicit
s4 : org.scalacheck.Shrink[A4], implicit
a5 : org.scalacheck.Arbitrary[A5], implicit
s5 : org.scalacheck.Shrink[A5], implicit
a6 : org.scalacheck.Arbitrary[A6], implicit
s6 : org.scalacheck.Shrink[A6]) : Unit
f -
the function to be converted into a property and checkedTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check(p : org.scalacheck.Prop, prms : org.scalacheck.Test.Params) : Unit
p -
the property to checkprms -
the test parametersTestFailedException -
if a test case is discovered for which the property doesn't hold.
def
check(p : org.scalacheck.Prop) : Unit
p -
the property to checkTestFailedException -
if a test case is discovered for which the property doesn't hold.
ScalaTest 1.0
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