What's the best way to validate the values of a Set in a unit test?

Question

Okay, often I'll have a method that returns a Set of some sort. The problem with unit testing such a method is that there is no guarantee an iteration over the set will always return the items in the same order.

Does anyone have any preferred method of validating a Set?

Peter

Answer 1

Two sets are equal, meaning they contain the same items, if they both contain one another

Assert.assertTrue(s1.containsAll(s2) && s2.containsAll(s1))

There's also SetUtils.isEqualSet

Answer 2

Just put your expected values in a Set and then use assertEquals on the expected and actual set. That works a charm, e.g.

Set<String> expected = new HashSet<String>(Arrays.asList("expected", "items"));
...
Set<String> actual = ...;
Assert.assertEquals(expected, actual);