@Test
    final void testNoBoomWithEmptyBuckets() {
        Bucket check = new Bucket();
        cache.updateDimensionPersistence(null, new Bucket());
        cache.updateDimensionPersistence(null, new Bucket());
        cache.updateDimensionPersistence(new Bucket(), check);
        assertEquals(0, check.entrySet().size());
    }
Functional test for point persistence layer.

@author Steinar Knutsen
container-core/src/test/java/com/yahoo/metrics/simple/DimensionsCacheTest.java