def test_sqrt():
    a = sqrt(interval(1, 4))
    assert a.start == 1
    assert a.end == 2

    a = sqrt(interval(0.01, 1))
    assert a.start == np.sqrt(0.01)
    assert a.end == 1

    a = sqrt(interval(-1, 1))
    assert a.is_valid is None

    a = sqrt(interval(-3, -1))
    assert a.is_valid is False

    a = sqrt(4)
    assert (a == interval(2, 2)) == (True, True)

    a = sqrt(-3)
    assert a.is_valid is False
def test_sqrt():
    a = sqrt(interval(1, 4))
    assert a.start == 1
    assert a.end == 2

    a = sqrt(interval(0.01, 1))
    assert a.start == np.sqrt(0.01)
    assert a.end == 1

    a = sqrt(interval(-1, 1))
    assert a.is_valid is None

    a = sqrt(interval(-3, -1))
    assert a.is_valid is False

    a = sqrt(4)
    assert (a == interval(2, 2)) == (True, True)

    a = sqrt(-3)
    assert a.is_valid is False