@Test
public void testToCNFDimacsClauses() {
Formula a = new Var("a");
Formula b = new Var("b");
Formula c = new Var("c");
Formula f = new Formula(a.not());
assertTrue("!a".equals(f.toString()));
List<IVecInt> clauses = f.toCNFDimacsClauses();
assertTrue(clauses.size() == 1);
IVecInt literals = clauses.get(0);
// expect {-1} array
assertTrue(literals.get(0) == -1);
f = new Formula(b.or(a.not()).or(c));
assertTrue("b or !a or c".equals(f.toString()));
clauses = f.toCNFDimacsClauses();
assertTrue(clauses.size() == 1);
literals = clauses.get(0);
// expect {2, -1, 3} array
assertTrue(literals.get(0) == 2);
assertTrue(literals.get(1) == -1);
assertTrue(literals.get(2) == 3);
}
@Test
public void testIsClause() {
Var a = new Var("a");
Var b = new Var("b");
Var c = new Var("c");
assertTrue(a.isClause());
assertTrue(b.isClause());
assertTrue(c.isClause());
// if a and b are both clauses, then so is (a or b)
Formula f = a.or(b);
assertTrue(f.isClause());
// if f is a literals and c is a literals, then so is (f or c)
assertTrue(f.or(c).isClause());
assertTrue(c.or(f).isClause());
Formula g = a.and(b);
assertFalse(g.isClause());
assertFalse(g.or(c).isClause());
assertFalse(c.or(g).isClause());
}