message: Add more normalization tests
diff: @@ -107,6 +107,45 @@ mod normalize {
  ).into(),
  );
  }
  +
  + // Passing the id function to itself should yield the id function
  + #[test]
  + fn id_app_id() {
  + let context = Context::new();
  +
  + let given_expr = r"
  + (\a : Type => \x : a => x)
  + ((a : Type) -> a -> a)
  + (\a : Type => \x : a => x)
  + ";
  + let expected_expr = r"\a : Type => \x : a => x";
  +
  + assert_eq!(
  + context.normalize(&parse(given_expr)),
  + context.normalize(&parse(expected_expr)),
  + );
  + }
  +
  + // Passing the id function to the 'const' combinator should yeild a
  + // function that always returns the id function
  + #[test]
  + fn const_app_id_ty() {
  + let context = Context::new();
  +
  + let given_expr = r"
  + (\a : Type => \b : Type => \x : a => \y : b => x)
  + ((a : Type) -> a -> a)
  + Type
  + (\a : Type => \x : a => x)
  + Type
  + ";
  + let expected_expr = r"\a : Type => \x : a => x";
  +
  + assert_eq!(
  + context.normalize(&parse(given_expr)),
  + context.normalize(&parse(expected_expr)),
  + );
  + }
  }
  mod infer {
  