import pytest

rclpy = pytest.importorskip('rclpy')


def test_the_node_constructs_with_default_parameters():
    """Declaring a parameter twice raises at construction, and nothing else exercises the node."""
    from hermes_vision.face_detector_node import FaceDetectorNode
    rclpy.init()
    try:
        node = FaceDetectorNode()
        assert node.detector.backend in ('yunet', 'haar')
        node.destroy_node()
    finally:
        rclpy.shutdown()


def test_detector_rate_can_be_changed_live():
    from rclpy.parameter import Parameter
    from hermes_vision.face_detector_node import FaceDetectorNode
    rclpy.init()
    try:
        node = FaceDetectorNode()
        assert abs(node.period - 0.25) < 1e-9
        assert node.set_parameters([Parameter('rate_hz', value=1.0)])[0].successful
        assert abs(node.period - 1.0) < 1e-9
        assert node.set_parameters([Parameter('rate_hz', value=0.01)])[0].successful
        assert abs(node.period - 2.0) < 1e-9                    # clamped to 0.5 Hz
        node.destroy_node()
    finally:
        rclpy.shutdown()