CollectionAssert in jUnit?

Question

Is there a jUnit parallel to NUnit\'s CollectionAssert?

Answer 1

Joachim Sauer's solution is nice but doesn't work if you already have an array of expectations that you want to verify are in your result. This might come up when you already have a generated or constant expectation in your tests that you want to compare a result to, or perhaps you have multiple expectations you expect to be merged in the result. So instead of using matchers you can can just use List::containsAll and assertTrue For Example:

@Test
public void testMerge() {
    final List expected1 = ImmutableList.of("a", "b", "c");
    final List expected2 = ImmutableList.of("x", "y", "z");
    final List result = someMethodToTest(); 

    assertThat(result, hasItems(expected1)); // COMPILE ERROR; DOES NOT WORK
    assertThat(result, hasItems(expected2)); // COMPILE ERROR; DOES NOT WORK

    assertTrue(result.containsAll(expected1));  // works~ but has less fancy
    assertTrue(result.containsAll(expected2));  // works~ but has less fancy
}