private void checkResults(Parent<? extends Collection<Child>> src, Parent<? extends Collection<Child>> dest) {
        Child srcChild1;
        Child srcChild2;
        //Because this is a non_cumulative mapping we expect that the resulting List is the same size as it was originally.
        Assert.assertEquals(dest.getChildren().size(), 2);

        // Because our child objects are comparable we know that either we have a list in the order we created if or a
        // sorted set so can iterate them to perform comparison.
        Iterator<Child> srcChildIter = src.getChildren().iterator();
        srcChild1 = srcChildIter.next();
        srcChild2 = srcChildIter.next();

        Iterator<Child> destChildIter = dest.getChildren().iterator();
        Child destChild1 = destChildIter.next();
        Child destChild2 = destChildIter.next();

        Assert.assertEquals(new Integer(1), destChild1.getId());
        Assert.assertEquals(srcChild1.getFirstName(), destChild1.getFirstName());
        //The lastname of the destination child should not have changed because the src had a null field and we have defined mapNull(false) in the childMapping builder.
        Assert.assertEquals("L1", destChild1.getLastName());

        Assert.assertEquals(new Integer(2), destChild2.getId());
        Assert.assertEquals(srcChild2.getFirstName(), destChild2.getFirstName());
        Assert.assertEquals(srcChild2.getLastName(), destChild2.getLastName());
    }
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