FastByIDMap<String> actual = new FastByIDMap<String>();
Map<Long, String> expected = Maps.newHashMapWithExpectedSize(1000000);
RandomGenerator r = RandomManager.getRandom();
for (int i = 0; i < 1000000; i++) {
double d = r.nextDouble();
Long key = (long) r.nextInt(100);
if (d < 0.4) {
assertEquals(expected.get(key), actual.get(key));
} else {
if (d < 0.7) {
assertEquals(expected.put(key, "bang"), actual.put(key, "bang"));