抽象类受保护的方法junit测试用例

Question

Consider the code:

abstract public class TigerFinderPage extends TigerPage
private Manager manager;
protected Manager getTiger()
{
    //  If we haven't already done so,  get the tiger.
    if (tiger== null) {
        try {
            tiger= EntityResolution.getTigerFromName(ResTools.resolveNoTranslation(getConfigBundle(), "tiger", ""));
        } catch (Exception e) {
            LogTools.error(logger, null, e);
            return null;
        }
    }
    return tiger;
}

TRY 1:

public class TigerFinderPageTest {

private TigerFinderPage tigerFinderPage;

@Before
public void setUp() throws Exception {

    TigerFinderPage = new TigerFinderPage () {
        @Override
        protected ResourceProvider getBundle() {
            return null;
        }

        @Override
        protected ResourceProvider getConfigBundle() {
            return null;
        }
    };
}

@Test
public void testTigerManager(){
    assertNull(tigerFinderPage.getTiger());
}
}

How Do I test the protected method when they are in different package? I have tried using reflection, but dont know how to implement it in this case.

Answer 1

Testing non-public members ties your tests to your implementation and makes it harder to refactor.

If it's significant enough that it can't be tested via the public interface then it must be separate functionality that could live in its own class à la Single Responsibility Principle

In this case I'd have a separate class and tests for LazyTigerFactory :

public final class LazyTigerFactory {
    private Manager manager;
    public Manager getTiger()
    {
        //  If we haven't already done so,  get the tiger.
        if (tiger == null) {
            try {
                tiger= EntityResolution.getTigerFromName(ResTools.resolveNoTranslation(getConfigBundle(), "tiger", ""));
            } catch (Exception e) {
                LogTools.error(logger, null, e);
                return null;
            }
        }
        return tiger;
    }
}

Then use it in your class:

abstract public class TigerFinderPage extends TigerPage
    private final LazyTigerFactory tigerFactory = new LazyTigerFactory();
    protected Manager getTiger(){
       return tigerFactory.getTiger();
    }

Benefits

• You can get full test coverage around the creation from the factory tests without cluttering your TigerFinderPage tests.
• You're free to easily change the LazyTigerFactory for another later.
• TigerFinderPage has fewer direct dependencies.
• TigerFinderPage is smaller, less Lazy/Entity boiler plate cluttering what this class really does (its single responsibility).
• You can even change to inject a factory interface completely decoupling it which may aid other tests.

Answer 2

One answer would be to follow JUnit's best practices and have both the production code and the code to test it in the same package , in order to allow accessing protected members, but in different source folders , so the non-production code doesn't disturb the production code. Eg, in maven's structure:

-- src
   +-- main
       +-- java
           +-- org
               +-- mypackage # Production code for org.mypackage
   +-- test
       +-- java
           +-- org
               +-- mypackage # Testing code for org.mypackage

If this is not an option, you can inherit from the abstract class and increase the visibility of the said method, just so the test can access it:

public class TigerFinderPageTest {        
    public static class TigerFinderPageDummy extends TigerFinderPage {
        @Override
        protected ResourceProvider getBundle() {
            return null;
        }

        @Override
        protected ResourceProvider getConfigBundle() {
            return null;
        }

        /** Note this method is PUBLIC */
        @Override
        public Manager getTiger() {
            return super.getTiger();
        }
    }

    private TigerFinderPageDummy tigerFinderPage;

    @Before
    public void setUp() throws Exception {
        tigerFinderPage = new TigerFinderPageDummy();
    }

    @Test
    public void testTigerManager(){
        assertNull(tigerFinderPage.getTiger());
    }
}