message: Add remaining test coverage
diff: @@ -1026,6 +1026,18 @@ mod alga_impls {
  mod test {
  use super::*;
  + #[test]
  + fn additive_operator_is_addition() {
  + let a = CsVec::new(2, vec![0], vec![2.]);
  + let b = CsVec::new(2, vec![0], vec![3.]);
  + assert_eq!(AbstractMagma::<Additive>::operate(&a, &b), &a + &b);
  + }
  +
  + #[test]
  + fn additive_identity_is_zero() {
  + assert_eq!(CsVec::<f64>::zero(), Identity::<Additive>::identity());
  + }
  +
  #[test]
  fn additive_inverse_is_negated() {
  let vector = CsVec::new(2, vec![0], vec![2.]);
  