If you subclass AbstractDependencyInjectionSpringContextTests (or any of its subclasses) then you don't need to lookup beans under test using
applicationContext.getBean("myBeanUnderTest")
.
By default these Spring classes use autowire by type so all you need to do is to add setter for required type.
E.g
public void setBeanUnderTest(MyBean bean) { this.beanUnderTest = bean; }