protected void configure() {
                mapping(
                        Child.class,
                        Child.class,
                        TypeMappingOptions.mapId(MAP_ID_CHILD),
                        TypeMappingOptions.mapNull(false)
                );
            }
Get the child mapping to use for the test, it is configured not to map nulls.

@return
core/src/test/java/com/github/dozermapper/core/functional_tests/builder/DeepMappingWithMapIdTest.java