Mocking of InitialContext not working in @Tested instantiation

[thwaerte]

I want to test a class that does a new InitialContext().lookup(String) in its constructor:

public class A {
    public A() throws NamingException {
        new InitialContext().lookup("something");
    }
}

If A is instantiated via @tested, InitialContext is not properly mocked. A NoInitialContextException is raised on calling lookup()

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:662)
    at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:307)
    at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:344)
    at javax.naming.InitialContext.lookup(InitialContext.java:411)
    at A.<init>(A.java:21)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

public class ATest {
    @Mocked
    InitialContext initialContext;
    @Tested
    A tested;
    @Test
    public void test() {
    }
}

Using the MockUp API does not help:

public class AMockUpTest {
    @Tested
    A tested;
    @Before
    public void thisDoesNotWork() {
        new InitialContextMock();
    }
    @Test
    public void test() {
    }
    static class InitialContextMock extends MockUp<InitialContext> {
        @Mock
        public void $init() {
        }
        @Mock
        public Object lookup(final String name) {
            return new Object();
        }
    }
}

If class A is instantiated in a @before method, everything seems to be working.

public class A2Test {
    @Mocked
    InitialContext initialContext;
    @Tested
    A tested;
    @Before
    public void thisWorks() throws NamingException {
        tested = new A();
    }
    @Test
    public void test() {
    }
}

public class AMockUp2Test {
    @Tested
    A tested;
    @Before
    public void thisWorks() throws NamingException {
        new InitialContextMock();
        tested = new A();
    }
    @Test
    public void test() {
    }
    static class InitialContextMock extends MockUp<InitialContext> {
        @Mock
        public void $init() {
        }
        @Mock
        public Object lookup(final String name) {
            return new Object();
        }
    }
}