java - Spring jUnit Testing properties file

Question

I have a jUnit Test that has its own properties file(application-test.properties) and its spring config file(application-core-test.xml).

One of the method uses an object instantiated by spring config and that is a spring component. One of the members in the classes derives its value from application.properties which is our main properties file. While accessing this value through jUnit it is always null. I even tried changing the properties file to point to the actual properties file, but that doesnt seem to work.

Here is how I am accessing the properties file object

@Component
@PropertySource("classpath:application.properties")
public abstract class A {

    @Value("${test.value}")
    public String value;

    public A(){
        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
    }

    public A(String text) {
        this();
        // do something with text and value.. here is where I run into NPE
    }

}

public class B extends A { 
     //addtnl code

    private B() {

    }


    private B(String text) {
         super(text)
    }
}

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations={"classpath:META-INF/spring/application-core-test.xml",
                             "classpath:META-INF/spring/application-schedule-test.xml"})
@PropertySource("classpath:application-test.properties")
public class TestD {

    @Value("${value.works}")
    public String valueWorks;

    @Test
    public void testBlah() {     
        SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this);
        B b= new B("blah");
        //...addtnl code

    }    
}      

Answer 1

Firstly, application.properties in the @PropertySource should read application-test.properties if that's what the file is named (matching these things up matters):

@PropertySource("classpath:application-test.properties ")

That file should be under your /src/test/resources classpath (at the root).

I don't understand why you'd specify a dependency hard coded to a file called application-test.properties. Is that component only to be used in the test environment?

The normal thing to do is to have property files with the same name on different classpaths. You load one or the other depending on whether you are running your tests or not.

In a typically laid out application, you'd have:

src/test/resources/application.properties

and

src/main/resources/application.properties

And then inject it like this:

@PropertySource("classpath:application.properties")

The even better thing to do would be to expose that property file as a bean in your spring context and then inject that bean into any component that needs it. This way your code is not littered with references to application.properties and you can use anything you want as a source of properties. Here's an example: how to read properties file in spring project?