JUnit 3 - Array contains a given element

assertThat(Arrays.asList(yourArray), hasItem(yourElement));

This will give you fine-grained information in the event of a test failure. It will print out your element and the collection it's looking in.

You can cast the array to a list:

assertTrue(Arrays.asList(yourArray).contains(yourElement));

Not a built-in assert, no. You'd need to use assertTrue() and check the array yourself using something like Arrays.binarySearch(), ArrayUtils.contains(), or your own method.