Assert.assertTrue(c1.binaryResolvents(c1).iterator().next().isEmpty());
// Check if resolve with self to an empty clause
c1.addPositiveLiteral(new Predicate("Pred1", new ArrayList<Term>()));
c1.addNegativeLiteral(new Predicate("Pred1", new ArrayList<Term>()));
Assert.assertNotNull(c1.binaryResolvents(c1));
Assert.assertEquals(1, c1.binaryResolvents(c1).size());
// i.e. resolving a tautology with a tautology gives you
// back a tautology.
Assert.assertEquals("[~Pred1(), Pred1()]", c1.binaryResolvents(c1)
.iterator().next().toString());