JUnit4 Parameterized Test

JUnit4ParameterizedTest.kt

import org.junit.Assert
import org.junit.Test
import org.junit.runner.RunWith
import org.junit.runners.Parameterized

class Multiplier {
    fun byTwo(value: Int): Int = value * 2
}

@RunWith(Parameterized::class)
class KotlinTest(
    private val paramValue: Int,
    private val expectedResult: Int
) {

    companion object {
        @JvmStatic
        @Parameterized.Parameters
        fun data() = listOf(
            arrayOf(0, 0),      // First test:  (paramValue = 0, expectedResult = 0)
            arrayOf(1, 2),      // Second test: (paramValue = 1, expectedResult = 2)
            arrayOf(2, 4),      // Third test:  (paramValue = 2, expectedResult = 4)
            arrayOf(-1, -2)     // Fourth test: (paramValue = -1, expectedResult = -2)
        )
    }

    @Test
    fun `Should multiply by two`() {
        val multiplier = Multiplier()

        val actualResult = multiplier.byTwo(paramValue)

        Assert.assertEquals(expectedResult, actualResult)
    }
}