assertj / Java comparing objects with list field ignoring order of elements in list

Question

I am looking to compare 2 list of objects (say Foo) in test.

List<Foo> fooA;
List<Foo> fooB;

Each Foo entry has one of the fields of type List (say Bar)

class Foo {
  private List<Bar> bars;
  ....
}

assertThat(fooA).isEqualTo(fooB);

Comparison fails because elements of bars are same but in different order.

Is there a way to compare them ignoring order?

I am not looking for below option.

assertThat(fooA).usingElementComparatorIgnoringFields("bars").isEqualTo(fooB);

Ideally I would like to compare all the fields

Rickrack

The comparison would fail even if the items were in the same order because the 2 lists are 2 different objects. – Infielder

See this other answer – Tolbert

Silly question: does Foo has an equals method defined? – Dupondius

Foo has an equals method defined and it checks if 2 list fields are equal. I tried updating it to check for containsAll instead but that din't help. – Rickrack

for groovy, use @EqualsAndHashCode. for java override equals/hashcode – Legation

Answer 1

you can do this with assertJ:

assertThat(fooA).usingRecursiveComparison().ignoringCollectionOrder().isEqualTo(fooB)

Soapstone

Recursive comparison allows you to compare field by field recursively even if they were not of the same type. – Mcavoy

This answer save my day on containsExactlyInAnyOrderElementsOf having list entry with OffsetDateTime with different offset issue that could be fixed with .usingRecursiveComparison().ignoringCollectionOrder().withComparatorForType(Comparator.comparing(a -> a.withOffsetSameInstant(ZoneOffset.UTC)),OffsetDateTime.class).isEqualTo(List.of(... – Arenicolous

Answer 2

What you are looking for is containsExactlyInAnyOrderElementsOf(Iterable) defined in IterableAssert (emphasis is mine) :

Verifies that the actual group contains exactly the given values and nothing else, in any order.

You could write so :

List<Foo> fooA;
List<Foo> fooB;
//...
assertThat(fooA).containsExactlyInAnyOrderElementsOf(fooB);

Morin

The question about comparing objects containing lists, not about comparing the lists themselves – Guerrilla