Why doesn't this code attempting to use Hamcrest's hasItems compile?

Question

Why does this not compile, oh, what to do?

import static org.junit.Assert.assertThat;
import static org.junit.matchers.JUnitMatchers.hasItems;

ArrayList<         


        

Answer 1

hasItems checks that a collection contains some items, not that 2 collections are equal, just use the normal equality assertions for that. So either assertEquals(a, b) or using assertThat

import static org.junit.Assert.assertThat;
import static org.hamcrest.CoreMatchers.is;

ArrayList actual = new ArrayList();
ArrayList expected = new ArrayList();
actual.add(1);
expected.add(2);
assertThat(actual, is(expected));

Alternatively, use the contains Matcher, which checks that an Iterable contains items in a specific order

import static org.junit.Assert.assertThat;
import static org.hamcrest.Matchers.contains;

ArrayList actual = new ArrayList();
actual.add(1);
actual.add(2);
assertThat(actual, contains(1, 2)); // passes
assertThat(actual, contains(3, 4)); // fails

If you don't care about the order use containsInAnyOrder instead.