sbt Test Interface for Frege QuickCheck

This sbt library enables you to run your tests written for Frege's QuickCheck with sbt test command.

sbt-frege-quickcheck is known to work with:

• sbt-1.1.2
• frege-3.24.100.1-jdk8
• sbt-frege-3.0.0

Great thanks to sbt, Frege and sbt-frege:

• sbt: https://github.com/sbt/sbt
• Frege: https://github.com/Frege/frege
• sbt-frege: https://github.com/earldouglas/sbt-frege

How to use

This library is published to the author's self-hosted repository. Please put the following into your build.sbt:

resolvers += "denshi-no-yamaoku.xyz" at "http://maven.denshi-no-yamaoku.xyz/"
libraryDependencies += "xyz.denshi_no_yamaoku" % "sbt-frege-quickcheck" % "0.2" % Test
testFrameworks += new TestFramework("xyz.denshi_no_yamaoku.quickcheck.QuickCheckFramework")

You need to give sbt the capability to compile Frege. If not done yet, please put the following into your project/plugins.sbt:

addSbtPlugin("com.earldouglas" % "sbt-frege" % "3.0.0")

See sbt-frege for details.

Put your tests into src/test/frege. Test modules should look like:

-- src/test/frege/example/FooTest.fr
module example.FooTest where

import frege.test.QuickCheck
import example.Foo (succs)

data Properties = pure native xyz.denshi_no_yamaoku.quickcheck.Properties

native module interface Properties where {}

intSuccs = property (\(xs::[Int]) -> succs xs == map succ xs)

knownToFail = expectFailure $ property (\(xs::[Int]) -> succs xs /= map succ xs)
unexpectedFail = property (\(xs::[Int]) -> succs xs == map pred xs)
unexpectedThrow = property (\(xs::[Int]) -> error "sorry!" :: Bool)

In this example the tested module is:

-- src/main/frege/example/Foo.fr
module example.Foo where

succs :: (Enum a) => [a] -> [a]
succs = map succ

The important part is native module interface Properties where {}. This declares that the module example.FooTest implements the marker interface xyz.denshi_no_yamaoku.quickcheck.Properties. The sbt test framework picks up the modules (classes, if seen from Java) that implements the interface as test suites.

See Frege #20 for the details of this syntax.

See Frege's own QuickCheck tests for example uses of QuickCheck.

Parallelism and Output

If your tests are run in parallel (the default), the output of QuickCheck may get intermixed. If you wish to disable parallelism for tests, put the following into your build.sbt:

Global / concurrentRestrictions += Tags.limit(Tags.Test, 1)

See the official documentation for the details of parallelism in sbt: https://www.scala-sbt.org/1.x/docs/Parallel-Execution.html