Question

I have a code like this:

public class MyTest extends TestCase {
    private MyObject mObject1;
    private MyObject mObject2;
    ...
    @Override
    public void setUp() throws Exception {
        super.setUp();
    }
    public void testSomething() {
        mObject1 = new MyObject();
        mObject2 = new MyObject();
    }
    public void testSomething2() {
      // Here I can't access the previously created objects mObject1 and 
      // mObject2, because they are again null. 
      // Why is that, if *my* setUp() method doesn't touch them?
    }

My guess is that JUnit instantiates the class again every time. Can someone please explain me the workflow?

Thanks.

Answer 1

JUnit will instantiate the class (MyTest) once per test and then execute the methods

• setUp()
• testXXX()
• tearDown()

until it runs all the methods that start with test and don’t receive any parameters. So in your example, Junit will instantiate MyTest twice. You can read more about this in the JUnit documentation.

Bear in mind that this is the old way of writing tests. From Junit 4 (I think) the preferred way is to use annotations. You can check the annotations documentation here.

As a side note, NUnit, reuses the instance of the test, so in the same scenario, it would only instantiate MyTest once.