AssertJ - how to check that an element is in a collection?

Question

Is there a way to check that an object is an element of some collection with AssertJ? Something like

assertThat(actualObject).isElementOf(collectionWithExpectedOptions);

I could do

assertThat(collectionWithExpectedOptions).contains(actualObject);

But I think there is a convention that the argument of assertThat() should be the actual rather than the expected thing.

Answer 1

try isIn:

Iterable<Ring> elvesRings = list(vilya, nenya, narya);

// assertion will pass:
assertThat(nenya).isIn(elvesRings);