How to assert that two Lists<String> are equal, ignoring order

Question

I am using AssertJ and I am trying to assert that two List<String> contain same strings, ignoring the order.

List<String> expected = Arrays.asList("Something-6144-77.pdf", "d-6144-77.pdf", "something-6144-78.pdf", "Something-6144-8068.pdf");
List<String> actual = new ArrayList<String>();

assertThat(actual.size()).isEqualTo(expected.size());

// This line gives the error: "The method containsExactlyInAnyOrder(String...) in the type ListAssert<String> is not applicable for the arguments (List<String>)"
assertThat(actual).containsExactlyInAnyOrder(expected);

How can I fix the compilation error below that is appearing when trying to use containsExactlyInAnyOrder()?

"The method containsExactlyInAnyOrder(String...) in the type ListAssert is not applicable for the arguments (List)"

Answer 1

Both the answers (by jlordo and by dasblinkenlight) work, but are workarounds rather than the correct way to do it.

There is a method in the AssertJ library for specifically checking if a List contains all values, regardless of order, in another Iterable. It is called containsOnlyElementsOf():

public SELF containsOnlyElementsOf(Iterable<? extends ELEMENT> iterable)

Same semantic as ObjectEnumerableAssert.containsOnly(Object[]) : verifies that actual contains all the elements of the given iterable and nothing else, in any order.

Example :

Iterable<Ring> rings = newArrayList(nenya, vilya);

// assertion will pass
assertThat(rings).containsOnlyElementsOf(newLinkedList(nenya, vilya)) .containsOnlyElementsOf(newLinkedList(nenya, nenya, vilya, vilya));

// assertion will fail as actual does not contain narya
assertThat(rings).containsOnlyElementsOf(newLinkedList(nenya, vilya, narya));
// assertion will fail as actual contains nenya assertThat(rings).containsOnlyElementsOf(newLinkedList(vilya));

So, this method is the one you should use, like below. There is no need to cast or transform your List to an Array.

assertThat(actual).containsOnlyElementsOf(expected);

---

As a side note, your assertion on the size of the list is redundant:

assertThat(actual.size()).isEqualTo(expected.size());

This is already covered in the assertion that the lists contain the same elements.

Finally, if you do need to assert that a list has a specific site, AssertJ has a built-in method for this (hasSameSizeAs()):

assertThat(actual).hasSameSizeAs(expected);