Question

I am used to JUnit running @Before methods in a superclass before @Before methods in a subclass. However, I’ve got a Groovy test class which inherits from another Groovy class, and they both contain @Before methods; the problem I have is that @Before method in the test class is running before the one in its superclass, and I’m getting NPEs from uninitialised variables (the superclass is supposed to take care of that).

The superclass is something like this:

import groovyx.net.http.RESTClient
import org.junit.Before

abstract class BaseTestClass {
    def client

    @Before
    void setUp() {
        client = new RESTClient()
    }
}

And the subclass is something like this:

import org.junit.Before

class TestClass extends BaseTestClass {

    @Before
    void setUp() {
        client.post(path: '/entity', body: '{"id":"test"}')
    }

    ...
}

This is a simplified version, but I get the error: java.lang.NullPointerException: Cannot invoke method post() on null object in the setUp() method of the subclass. Any ideas what could cause this behaviour? All the docs say it should be the other way round, and I’ve never previously experienced any different.

I’m running using the maven-failsafe-plugin, junit-4.10 and jdk-1.6.0_31. Interestingly, I have other Groovy test classes in the same place (same package, same project, same directory) which do not suffer from this problem – the ordering of @Before methods is correct; furthermore, it appears to be deterministic – it’s always the same test class that has the problem.

Thanks!

Answer 1

You named both of your @Before methods setUp(). The child’s setUp() method overrides the parent’s one. So the line client = new RESTClient() is never called.

Just pick another name.