*/
@Test
@Generator(klass = double.class, generator = PercentageGen.class)
public void testNullGen(final double d) {
final int iterations = 10000;
Distribution rand = Arbitrary.defaultDistribution();
NullGen<Integer> ngen = new NullGen<Integer>(new IntegerSimpleGen(), d);
int nulls = 0;
for (int i = 0; i < iterations; ++i) {
if (ngen.arbitrary(rand, 0, 100) == null) {
nulls++;