org.scalacheck.contrib.ScalaCheckJUnit.scala Maven / Gradle / Ivy

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JUnit 4 Runner for ScalaCheck by Oscar Renalias; modern mavenisation by Matt Gumbley
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package org.scalacheck.contrib

import org.junit.runner.Description
import org.scalacheck._
import org.scalacheck.{Test => ScalaCheckTest}
import org.scalacheck.Test.Parameters
import org.scalacheck.util.ConsoleReporter
import org.junit.runner.notification.{Failure, RunNotifier}
import org.scalacheck.Prop.Result
import java.lang.{Boolean, Throwable}


/**
  * This a JUnit runner that allows to run ScalaCheck properties (created into an object that implements
  * Properties) as part of a JUnit test suite. Each property will be counted as a failure or passed test
  * by JUnit.
  *
  * Properties are written in the exact same way as pure ScalaCheck; the only aifference is that the test suite class
  * needs to be annotated with @RunWith[classOf[ScalaCheckJUnitPropertiesRunner]] so that JUnit knows how to run
  * the tests
  */
class ScalaCheckJUnitPropertiesRunner(suiteClass: java.lang.Class[Properties]) extends org.junit.runner.Runner {

    private val properties = suiteClass.newInstance

    lazy val getDescription = createDescription(properties)

    /**
      * Create a description
      */
    private def createDescription(props: Properties): Description = {
        val description = Description.createSuiteDescription(props.name)
        props.properties.foreach(p => Description.createTestDescription(p._2.getClass, p._1))
        description
    }

    // Our custom test callback, used to keep JUnit's runner updated about test progress
    private[contrib] class CustomTestCallback(notifier:RunNotifier, desc: Description) extends Test.TestCallback {
        // TODO: is it even possible to obtain the correct stack trace? ScalaCheck doesn't throw Exceptions for property failures!
        def failure = new Failure(desc, new Throwable("ScalaCheck property did not hold true"))

        /** Called whenever a property has finished testing */
        override def onTestResult(name: String, res: Test.Result) = {
            res.status match {
                case Test.Passed => {} // Test passed, nothing to do
                case Test.Proved(_) => {} // Test passed, nothing to do
                case Test.Exhausted => notifier.fireTestIgnored(desc) // exhausted tests are marked as ignored in JUnit
                case _ => notifier.fireTestFailure(failure) // everything else is a failed test
            }
        }
    }

    // we'll use this one to report status to the console, and we'll chain it with our custom reporter
    val consoleReporter = new ConsoleReporter(1)

    /**
      * Run this Suite of tests, reporting results to the passed RunNotifier.
      * This class's implementation of this method invokes run on an instance of the
      * suiteClass Class passed to the primary constructor, passing
      * in a Reporter that forwards to the  RunNotifier passed to this
      * method as notifier.
      *
      * @param notifier the JUnit RunNotifier to which to report the results of executing
      * this suite of tests
      */
    def run(notifier: RunNotifier) {

        properties.properties.map({ propTuple =>
            propTuple match {
                case (desc, prop) => {
                    val descObj = Description.createTestDescription(prop.getClass, desc)

                    // TODO: is there a better way to do this? It seems that JUnit is not printing the actual name of the test case to the screen as it runs
                    print("Running property: " + desc)

                    notifier.fireTestStarted(descObj)
                    ScalaCheckTest.check(new Parameters.Default {
                        override val testCallback: AnyRef with Test.TestCallback = consoleReporter chain
                          new CustomTestCallback(notifier, descObj)
                    }, prop)
                    notifier.fireTestFinished(descObj)
                }
            }
        })
    }

    /**
      * Returns the number of tests that are expected to run when this ScalaTest Suite
      * is run.
      *
      * @return the expected number of tests that will run when this suite is run
      */
    override def testCount() = properties.properties.size
}