message: add rotation_matrix_2d test
diff: @@ -30,3 +30,12 @@ fn ellipse() -> Result<()> {
  assert_eq!(Point::new(100, 300), pts.get(5)?);
  Ok(())
  }
  +
  +#[test]
  +fn get_rotation_matrix_2d() -> Result<()> {
  + let mat = imgproc::get_rotation_matrix_2d(Point2f::new(10., 10.), 90., 2.)?;
  + assert_eq!(Size::new(3, 2), mat.size()?);
  + assert_eq!(*mat.at_2d::<f64>(0, 0)?, *mat.at_2d::<f64>(1, 1)?);
  + assert_eq!(-*mat.at_2d::<f64>(0, 1)?, *mat.at_2d::<f64>(1, 0)?);
  + Ok(())
  +}
  