List diffs in the context of usingRecursiveComparison()

Question

This is an AssertJ specific question. Consider the tests below where two lists are compared first directly and then nested in some other object through usingRecursiveComparison() .

public class RecursiveComparisonWithNestedListsTest {
    @Test
    void topLevelList() {
        assertThat(List.of("Bob", "Chris"))
                .containsExactlyElementsOf(List.of("Bob"));
    }
    @Test
    void nestedList() {
        assertThat(new Person("Amy", List.of("Bob", "Chris")))
                .usingRecursiveComparison()
                .isEqualTo(new Person("Amy", List.of("Bob")));
    }
}
record Person(String name, List<String> friends) {
}

In the first case the message is more helpful, specifying the missing element:

Expecting actual:
  ["Bob", "Chris"]
to contain exactly (and in same order):
  ["Bob"]
but some elements were not expected:
  ["Chris"]

In the second case the message just mentions that the size differs:

Expecting actual:
  Person[name=Amy, friends=[Bob, Chris]]
to be equal to:
  Person[name=Amy, friends=[Bob]]
when recursively comparing field by field, but found the following difference:

field/property 'friends' differ:
- actual value  : ["Bob", "Chris"]
- expected value: ["Bob"]
actual and expected values are collections of different size, actual size=2 when expected size=1

This is just a simple example; the actual use case involves more complex objects and much larger lists. In that context, specifying what item is missing from the list makes a big difference. This brings me to my question: Is there any way to configure the recursive comparison to compare lists just like in the first example?

I certainly have the workaround to ignore the list in the recursive comparison and then assert list equality separately, but I was wondering if there's some trick to get it all in one step.

Answer 1

No there is no such capability at the moment.