java - 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

private void someMethod(int id1, int id2, HashMap map){
    ......some code........

    Context ctx = new InitialContext();
    Object ref = ctx.lookup("com.java.ejbs.MyEJB");

    EJBHome ejbHome = (EJBHome)PortableRemoteObject.narrow(ref, EJBHome.class);
    EJBBean ejbBean = (EJBBean)PortableRemoteObject.narrow(ejbHome.create(), EJBBean.class);
    ejbBean.someMethod(id1,name);

    .......some code.......}

My unit test for above method

@Test
public void testsomeMethod() throws Exception {

    .......setting initial code...
    //Mock context and JNDI

    InitialContext cntxMock = PowerMock.createMock(InitialContext.class);
    PowerMock.expectNew(InitialContext.class).andReturn(cntxMock);
    expect(cntxMock.lookup("com.java.ejbs.MyEJB")).andReturn(refMock);               

    ..........some code..........

    PowerMock.replayAll();
    Whitebox.invokeMethod(ObjectOfsomeMethodClass, "someMethod", id1, id2, map);


}

when the Whitebox.invokeMethod(ObjectOfsomeMethodClass, "someMethod", id1, id2, map) method invokes it gives following exception.

javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file:  java.naming.factory.initial
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:645)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:325)
at javax.naming.InitialContext.lookup(InitialContext.java:392)

I believe, although we mock the Context in test method, it does not use the mock object when calling Whitebox.invokeMethod(ObjectOfsomeMethodClass, "someMethod", id1, id2, map) method, instead of that its trying to invoke the Context ctx = new InitialContext(); method in original method(someMethod).

Answer 1

Handmade

As InitialContext doc says, you can provide your own factory for InitialContext objects, using java.naming.factory.initial system property. When the code runs inside application server, the system property is set by the server. In our tests, we provide our own implementation of JNDI.

Here's my Mockito only solution: I defined a custom InitialContextFactory class, that returns a mock of InitialContext. You customize the mock as you wish, probably to return more mocks on lookup calls.

public class PlainTest {
  @Mock InitialContextFactory ctx;
  @InjectMocks Klasa1 klasa1;

  public static class MyContextFactory implements InitialContextFactory
  {
    @Override
    public Context getInitialContext(Hashtable<?, ?> environment) throws NamingException {
      ConnectionFactory mockConnFact = mock(ConnectionFactory.class);
      InitialContext mockCtx = mock(InitialContext.class);
      when(mockCtx.lookup("jms1")).thenReturn(mockConnFact);
      return mockCtx;
    }
  }

  @Before
  public void setupClass() throws IOException
  {
    MockitoAnnotations.initMocks(this);
    System.setProperty("java.naming.factory.initial",
      this.getClass().getCanonicalName() + "$MyContextFactory");
  }

Spring (added by edit)

If you don't mind leveraging Spring Framework for testing purposes, here's their simple solution: SimpleNamingContextBuilder:

SimpleNamingContextBuilder builder = new SimpleNamingContextBuilder();
DataSource ds = new DriverManagerDataSource(...);
builder.bind("java:comp/env/jdbc/myds", ds);
builder.activate();

It's ok to put it in @Before or @BeforeClass. After activate(), jndi data will be pulled from spring dummy.