How to mock InitialContext constructor in unit testing

Question

when I try to mock following method(Method is using remote EJB call for business logic) for the Junit test, it gives javax.naming.NoInitialContextException

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Answer 1

Adding to Jarekczek's answer (Thanks for it!!). Though it is an old question I would like to share my version of it in case it helps someone. I faced the same problem and one might just want to mock IntialContext only in a IntialContextFactory implementation class and it would be a better idea to use this mocked object in other tests or base test classes to avoid duplication.

public class MyContextFactory implements InitialContextFactory { 
    // Poor Singleton approach. Not thread-safe (but hope you get the idea)
    private static InitialContext mockInitialContext;
    @Override
    public Context getInitialContext(Hashtable hshtbl) throws NamingException {
        if(mockInitialContext == null) {
            mockInitialContext = mock(InitialContext.class);
        }
        return mockInitialContext;
    }
}

public class TestClass {
    private DataSource mockDataSource;
    private Connection mockConnection;

    protected void mockInitialContext() throws NamingException, SQLException {
        System.setProperty("java.naming.factory.initial", "com.wrapper.MyContextFactory");

        InitialContext mockInitialContext = (InitialContext) NamingManager.getInitialContext(System.getProperties());
        mockDataSource = mock(DataSource.class);
        mockConnection = mock(Connection.class);

        when(mockInitialContext.lookup(anyString())).thenReturn(mockDataSource);
        when(mockDataSource.getConnection()).thenReturn(mockConnection);

        try {
            when(mockDataSource.getConnection()).thenReturn(mockConnection);
        } catch (SQLException ex) {
            Logger.getLogger(CLASSNAME).log(Level.SEVERE, null, ex);
        }
    }
}

Reason behind taking this approach being if someone wants to use DataSource or any other resource provided by JNDI in a different way for different tests, you can follow this approach. There shall be just one instance created for IntialContext unless a multi-threaded test tries to access it simultaneously (don't know why would one try to do that!). That instance can be used in all places to get JNDI objects you want and use them as you want.

Hope this helps!

"Make sure you wash your hands before every meal and avoid System.out.println while debugging for healthy lifestyle"