How to write JUNIT test case for mocking?

Question

I have the method similar to following structure.

method1(Object obj,byte[] myarray)
{
    mymanager.dbcall1();
    mymanager2.dbcall2();
}

Now I want to write the JUNIT test case which can actually mock these managers who are doing the dbcalls ?Finally I want to compare the results. These managers are available only at run time of the application.

the class that holds method1, does it have getters and setters for mymanager or mymanager2? How are they created at runtime? — Simon Hellinger, Mar 14 '13 at 13:17

score 1 · Accepted Answer · answered Mar 14 '13 at 13:20

Do you want to test method1()? If so, I assume that you have a setter for mymanager in the enclosing class, which will enable you to (using Mockito):

@Before
public void setUp()
{
    MyClass my = new MyClass();
    MyManager mgr = mock( MyManager.class );
    my.setManager( mgr );

    // Similar for mymanager2
}

Then all method calls on mgr will just return null. If you need other return values, the doReturn(...).when( mgr ).dbcall1() construct can be used.

Cheers,

score 0 · Answer 2 · edited May 23 '17 at 12:04

0

Here you go, I searched on stack overflow and found pretty much something that someone has asked before:

Testing an EJB with JUnit

It's based on EJB but we don't know what you are using right now, but this might have some common principles.

edited May 23 '17 at 12:04

Community

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answered Mar 14 '13 at 13:21

Davos555

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score 0 · Answer 3 · answered Mar 14 '13 at 13:24

First, you'll need some dependency injection. There are many ways to accomplish this, but here's a simple one:

private I_DatabaseManager mymanager = null;

method1(Object obj,byte[] myarray)
{
    getDatabaseManager().dbcall1();
    getDatabaseManager().dbcall2();
}

private I_DatabaseManager getDatabaseManager() {
    if (mymanager == null) {
          return getProductionImplementationOfDatabaseManager();
    }
    return mymanager;
}

protected void setDatabaseManagerImplementation(I_DatabaseManager newImplementation) {
    mymanager = newImplementation;
}

Then, in your test code you can create a mock class which implements the I_DatabaseManager interface and set this mock implementaion in your test.

How to write JUNIT test case for mocking?

3 Answers3