def test_unconstructed_singleton(self):
a = Objective()
self.assertEqual(a._constructed, False)
self.assertEqual(len(a), 0)
try:
a()
self.fail("Component is unconstructed")
except ValueError:
pass
try:
a.expr
self.fail("Component is unconstructed")
except ValueError:
pass
try:
a.sense
self.fail("Component is unconstructed")
except ValueError:
pass
a.construct()
a.set_sense(minimize)
self.assertEqual(len(a), 1)
self.assertEqual(a(), None)
self.assertEqual(a.expr, None)
self.assertEqual(a.sense, minimize)
a.sense = maximize
self.assertEqual(len(a), 1)
self.assertEqual(a(), None)
self.assertEqual(a.expr, None)
self.assertEqual(a.sense, maximize)
