import org.junit.Test;
import org.junit.Ignore;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;

import java.util.Arrays;
import java.util.Collection;

import static org.junit.Assert.assertEquals;

@RunWith(Parameterized.class)
public class RaindropConverterTest {

    private int inputNumber;
    private String outputFromRaindropConversion;

    @Parameters(name = "{index}: expected input number {0} to be converted to \"{1}\"")
    public static Collection<Object[]> data() {
        return Arrays.asList(new Object[][]{
                // Non-primes
                {1, "1"},
                {8, "8"},
                {52, "52"},

                // Numbers with 3 as a prime factor
                {3, "Pling"},
                {6, "Pling"},
                {9, "Pling"},
                {27, "Pling"},

                // Numbers with 5 as a prime factor
                {5, "Plang"},
                {10, "Plang"},
                {25, "Plang"},
                {3125, "Plang"},

                // Numbers with 7 as a prime factor
                {7, "Plong"},
                {14, "Plong"},
                {49, "Plong"},

                // Numbers with multiple activating prime factors
                {15, "PlingPlang"},
                {21, "PlingPlong"},
                {35, "PlangPlong"},
                {105, "PlingPlangPlong"},
        });
    }

    public RaindropConverterTest(int inputNumber, String outputFromRaindropConversion) {
        this.inputNumber = inputNumber;
        this.outputFromRaindropConversion = outputFromRaindropConversion;
    }


    @Test
    public void test() {
        assertEquals(outputFromRaindropConversion, new RaindropConverter().convert(inputNumber));
    }
}

import org.junit.Test;
import org.junit.Ignore;

import java.util.Arrays;
import java.util.Collection;

import static org.junit.Assert.assertEquals;

public class RaindropConverterTest {

    private RaindropConverter raindropConverter = new RaindropConverter();

    @Test
    public void soundFor1Is1() {
        assertEquals("1", raindropConverter.convert(1));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor3OrNumberWithOnlyDistinctFactorOf3() {
        assertEquals("Pling", raindropConverter.convert(3));
        assertEquals("Pling", raindropConverter.convert(6));
        assertEquals("Pling", raindropConverter.convert(9));
        assertEquals("Pling", raindropConverter.convert(27));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor5OrNumberWithOnlyDistinctFactorOf5IsPlang() {
        assertEquals("Plang", raindropConverter.convert(5));
        assertEquals("Plang", raindropConverter.convert(10));
        assertEquals("Plang", raindropConverter.convert(25));
        assertEquals("Plang", raindropConverter.convert(3125));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor7OrNumberWithOnlyDistinctFactorOf7IsPlong() {
        assertEquals("Plong", raindropConverter.convert(7));
        assertEquals("Plong", raindropConverter.convert(14));
        assertEquals("Plong", raindropConverter.convert(49));
    }

    @Ignore("Remove to run test")
    @Test
    public void noSoundFor2Cubed() {
        assertEquals("8", raindropConverter.convert(8));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor15IsPlingPlang() {
        assertEquals("PlingPlang", raindropConverter.convert(15));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor21IsPlingPlong() {
        assertEquals("PlingPlong", raindropConverter.convert(21));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor35IsPlangPong() {
        assertEquals("PlangPong", raindropConverter.convert(35));
    }

    @Ignore("Remove to run test")
    @Test
    public void noSoundFor52() {
        assertEquals("52", raindropConverter.convert(52));
    }

    @Ignore("Remove to run test")
    @Test
    public void soundFor105IsPlingPlangPlong() {
        assertEquals("PlingPlangPong", raindropConverter.convert(105));
    }

}

Update RaindropConverterTest.java