def _add_turbine_marker(self, turbine, coords, wind_direction):
a = Coordinate(coords.x, coords.y - turbine.rotor_radius)
b = Coordinate(coords.x, coords.y + turbine.rotor_radius)
a.rotate_z(turbine.yaw_angle - wind_direction, coords.as_tuple())
b.rotate_z(turbine.yaw_angle - wind_direction, coords.as_tuple())
plt.plot([a.xprime, b.xprime], [a.yprime, b.yprime], 'k', linewidth=1)
def test_rotation_on_z():
"""
Coordinate at 1, 1 rotated 90 degrees around z axis should result in 1,-1
"""
test_class = CoordinateTest()
coordinate = Coordinate(test_class.x, test_class.y)
coordinate.rotate_z(np.pi / 2.0)
assert pytest.approx(coordinate.xprime) == -1.0 and pytest.approx(
coordinate.yprime) == 1.0