@Test
public void testCallButBothAttrsNull_shouldThrowException() throws Exception {

    Map<String, Object> propData =
        ImmutableMap.of("testprop", (Object) new String[]{ "bla", "bleh", });
    TestInterface mockService = mockServiceWithProps(propData);
    MethodCall c = new MethodCall("test", new Object[]{ 42 });
    try {
        requestHandler.handleCall(c);
        fail("IllegalArgumentException expected");
    } catch (IllegalArgumentException e) {
        verifyZeroInteractions(mockService);
    }
}