CODEWITHSUNDEEP
unit-testingscalajunitjunit4
towi
towi

Reputation: 22267

Parameterized Unit Tests in Scala (with JUnit4)

Is there a way to implement a parameterized unit test with Scala? Currently I use JUnit4 in the rest of my programs and I would like to continue using only "standard" APIs.

I found an example for Junit4 with Groovy, but I have problems defining the static parts. Could be, because I am also quite new with Scala :-)

I am currently as fas as

import org.junit.Test
import org.junit.Assert._

import org.junit.runner.RunWith
import org.junit.runners.Parameterized
import org.junit.runners.Parameterized.Parameters

@RunWith(classOf[Parameterized])
class MyTest extends junit.framework.TestCase {

    @Parameters object data {
        ...
    }

    @Parameter ...

    @Test
    def testFunction() = {
    }

Upvotes: 9

Views: 5507

Answers (2)

Horst Dehmer
Horst Dehmer

Reputation: 369

That's quite a nuisance, but it works. Two important things I discovered: companion object must come after test class, the function returning the parameters must return a collection of arrays of AnyRef (or Object). arrays of Any won't work. That the reason I use java.lang.Integer instead of Scala's Int.

import java.{util => ju, lang => jl}
import org.junit.Test
import org.junit.runner.RunWith
import org.junit.runners.Parameterized
import org.junit.runners.Parameterized.Parameters

@RunWith(value = classOf[Parameterized])
class JUnit4ParameterizedTest(number: jl.Integer) {
    @Test def pushTest = println("number: " + number)
}

// NOTE: Defined AFTER companion class to prevent:
// Class com.openmip.drm.JUnit4ParameterizedTest has no public
// constructor TestCase(String name) or TestCase()
object JUnit4ParameterizedTest {

    // NOTE: Must return collection of Array[AnyRef] (NOT Array[Any]).
    @Parameters def parameters: ju.Collection[Array[jl.Integer]] = {
        val list = new ju.ArrayList[Array[jl.Integer]]()
        (1 to 10).foreach(n => list.add(Array(n)))
        list
    }
}

The output should be as expected:

Process finished with exit code 0
number: 1
number: 2
number: 3
number: 4
number: 5
number: 6
number: 7
number: 8
number: 9
number: 10

Upvotes: 9

Peter Niederwieser
Peter Niederwieser

Reputation: 123890

You are probably better off with ScalaTest or Specs. The latter definitely supports parameterized tests, and is widely used in the Scala community. JUnit's syntax for parameterized tests is pretty horrible, and its reliance on static declarations won't make your task easier in Scala (probably you need a companion object).

Upvotes: 2

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