def test_relation_with_offset_to_string(self):
e = lp.Expression({'x1': 4}, -20)
r = lp.Relation(lp.Relation.Less, e)
self.assertEqual(str(r), '4*x1 <= 20')
def test_relation_without_offset_to_string(self):
e = lp.Expression({'x1': 1})
r = lp.Relation(lp.Relation.Equals, e)
self.assertEqual(str(r), 'x1 == 0')
def test_create_relation(self):
e = lp.Expression({'x1': 4})
r = lp.Relation(lp.Relation.Greater, e)
self.assertEqual(r.expression, e)
self.assertEqual(r.sense, lp.Relation.Greater)