Junit 4如何在测试套件中初始化并将其传递给测试类

Question

Is there a way in Junit4 to pass some pre-initialized data like http connections that you initialize using say '@ClassRule' in the class annotated with '@RunWith(Suite.class)' to all child (ie suite) test classes? Also how to ensure that the classes in the suite cannot be run individually?

eg

class A {
    private HttpClient client;
    @Test
    public void someTest() {
        client.execute(...);
        ...
    }
 }

 @RunWith(Suite.class)
 @Suite.SuiteClasses({A.class})
 public class Suite {
     private static HttpClient client;
     @ClassRule
     public static ExternalResource resource= new ExternalResource() {
         @Override
         protected void before() throws Throwable {
             client = new DefaultHttpClient();
         } 
     }

Thanks,

Paddy

Answer 1

I don't think that you can achieve that with JUnit.

The only possibility I see is to use an abstract class and inherit that one in every test class.

public abstract class AbstractTest {
  @ClassRule
  public static ExternalResource resource= new ExternalResource() {
    //...
  }
}

public class MyTest extends AbstractTest {
}

Also how to ensure that the classes in the suite cannot be run individually?

I don't think that is possible either.

But why would you want that? After fixing a single failing test, do you really want to re-run all tests to check if one test is working? (Of course, the fix could have introduced side effects but you can re-run all tests when you know that your fixed test is working.) Moreover, the tests should be able to run independently.

Answer 2

When you're using the out-of-the-box Runners of JUnit you would get any access from a test Suite to its child tests. Instantiation of the test classes is done internally in the framework.

If you want to pass information/state from one test to another, I'd suppose to implement some kind of "context". Eg a Singleton with a static Getter and Setter for the context that allows your suite to store an Object and to read it later on from your tests.