message: Added tests for error cases in ArgminInv impl of nalgebra backend
diff: @@ -12,7 +12,7 @@ use nalgebra::{
  };
  use std::fmt;
  -#[derive(Debug, Clone, thiserror::Error)]
  +#[derive(Debug, thiserror::Error, PartialEq)]
  struct InverseError;
  impl fmt::Display for InverseError {
  @@ -64,6 +64,20 @@ mod tests {
  }
  }
  }
  +
  + item! {
  + #[test]
  + fn [<test_inv_error $t>]() {
  + let a = Matrix2::new(
  + 2 as $t, 5 as $t,
  + 4 as $t, 10 as $t,
  + );
  + let err = <Matrix2<$t> as ArgminInv<Matrix2<$t>>>::inv(&a).unwrap_err().downcast::<InverseError>().unwrap();
  + assert_eq!(err, InverseError {});
  + assert_eq!(format!("{}", err), "Non-invertible matrix");
  + assert_eq!(format!("{:?}", err), "InverseError");
  + }
  + }
  };
  }
  