'Test domain for power.'

def test_power(self):

    dom = sqrt(self.a).domain
    Problem(Minimize(self.a), dom).solve()
    self.assertAlmostEquals(self.a.value, 0)
    dom = square(self.a).domain
    Problem(Minimize(self.a), (dom + [(self.a >= (-100))])).solve()
    self.assertAlmostEquals(self.a.value, (-100))
    dom = (self.a ** (-1)).domain
    Problem(Minimize(self.a), (dom + [(self.a >= (-100))])).solve()
    self.assertAlmostEquals(self.a.value, 0)
    dom = (self.a ** 3).domain
    Problem(Minimize(self.a), (dom + [(self.a >= (-100))])).solve()
    self.assertAlmostEquals(self.a.value, 0)
