def test_add(self):
    t1 = formula.Term('t1')
    t2 = formula.Term('t2')
    f = (t1 + t2)
    assert_(isinstance(f, formula.Formula))
    assert_(f.hasterm(t1))
    assert_(f.hasterm(t2))
def test_add(self):
    t1 = formula.Term('t1')
    t2 = formula.Term('t2')
    f = (t1 + t2)
    assert_(isinstance(f, formula.Formula))
    assert_(f.hasterm(t1))
    assert_(f.hasterm(t2))