assert collection does not contain item

Question

Using the hamcrest library for Java, what's a nicely readable way to do the opposite of:

assertThat(someCollection, hasItem(someItem))

I want to make sure someCollection does not contain item someItem

Answer 1

Negate the hasItem assertion

assertThat(someCollection, not(hasItem(someItem)))

Answer 2

If you need to Assert an Array, the same logic use not(hasItemInArray())

final String[] availableIds = {"123", "321"};
final String userId = "333";

softAssert.assertThat("Id not found", availableIds, not(hasItemInArray(userId)));
softAssert.assertAll();