'Test presolve with parameters.'

def test_presolve_parameters(self):

    gamma = Parameter(sign='positive')
    x = Variable()
    obj = Minimize(x)
    prob = Problem(obj, [(gamma == 1), (x >= 0)])
    gamma.value = 0
    prob.solve(solver=s.SCS)
    self.assertEqual(prob.status, s.INFEASIBLE)
    gamma.value = 1
    prob.solve(solver=s.SCS)
    self.assertEqual(prob.status, s.OPTIMAL)
