Using parameterized JUnit tests with the play! framework

Question

I want to use parameterized JUnit tests on a play! framework (1.2.5) application.

This is my very simple test example:

import java.util.Arrays;
import java.util.List;

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

import play.test.FunctionalTest;

@RunWith(Parameterized.class)
public class ParameterizedExampleTest extends FunctionalTest {

    private int i;

    @Parameters
    public static List<Object[]> parameters() {
        return Arrays.asList(new Object[][] {{1},{2},{3}});
    }

    public ParameterizedExampleTest(int i) {
        this.i = i;
    }

    @Test
    public void someTest() {
        System.out.println("i is " + i);
    }
}

When I run the test, I get an IllegalArgumentException telling me "Test class can only have one constructor". I perfectly agree with that as FunctionalTest extends BaseTest which has a @RunWith(PlayJUnitRunner.class) annotation and the PlayJUnitRunner has a constructor.

Any help welcome!

Answer 1

I found a rather nice solution:

import java.util.Arrays;
import java.util.List;

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

import play.test.FunctionalTest;

@RunWith(Parameterized.class)
public class ParameterizedExampleTest extends FunctionalTest {

    @Parameter(0)
    public int i;

    @Parameters
    public static List<Object[]> parameters() {
        return Arrays.asList(new Object[][] {{1},{2},{3}});
    }

    @Test
    public void someTest() {
        System.out.println("i is " + i);
    }
}

You have to mark the parameters with the @Parameter(...) Annotation and the number of the parameter in the parameters array. No constructor is needed hence it runs smoothly with play.

Drawback: You will need JUnit 4.11 as this feature is not implemented in 4.10 which is what play (1.2.5) comes with.