Even if it isn't for performance, I think it can improve readability.

Perhaps it is even better to do: 

```
public void testPredicatesAgainstANullField() {
	testPredicateWithNullField(Predicates.lessEqual("nullField", 1));
	testPredicateWithNullField(Predicates.in("nullField", 1));
	...
}

public void testPredicateWithNullField(Predicate p){
	 Object object = new DummyObject();
	 assertFalse(p.apply(object));
}
```