@Test
public void testIsPhrase() {
Var a = new Var("a");
Var b = new Var("b");
Var c = new Var("c");
assertTrue(a.isPhrase());
assertTrue(b.isPhrase());
assertTrue(c.isPhrase());
// if a and b are both phrases, then so is (a and b)
Formula f = a.and(b);
assertTrue(f.isPhrase());
// if f is a phrase and c is a phrase, then so is (f and c)
assertTrue(f.and(c).isPhrase());
assertTrue(c.and(f).isPhrase());
Formula g = a.or(b);
assertFalse(g.isPhrase());
assertFalse(g.and(c).isPhrase());
assertFalse(c.and(g).isPhrase());
}
