feat(kernel): a type for which Mass a day says

The lectionary's four-step chain already decides whether a day says its own
proper, its own slug's entry, the preceding Sunday's Mass or a Common, and
then discards that decision once the citations are out. An ordo needs to
print it.

1 files changed, 29 insertions, 0 deletions

diff --git a/test/test_mass_formulary.ml b/test/test_mass_formulary.ml
new file mode 100644
index 0000000..b940161
--- /dev/null
+++ b/test/test_mass_formulary.ml
@@ -0,0 +1,29 @@
+module MF = Colitur_kernel.Mass_formulary
+module Slug = Colitur_kernel.Slug
+
+let slug s = Slug.of_string_exn s
+
+let test_round_trips_through_sexp () =
+  let f = { MF.said = slug "ef-time-after-pentecost-sunday-9"; via = MF.Preceding_sunday } in
+  let f' = MF.t_of_sexp (MF.sexp_of_t f) in
+  Alcotest.(check string) "slug survives" (Slug.to_string f.MF.said) (Slug.to_string f'.MF.said);
+  Alcotest.(check bool) "source survives" true (f.MF.via = f'.MF.via)
+
+(* [to_string] is what an ordo line shows. It names the SOURCE, not the slug,
+   because the slug is a key and the reader wants "of the preceding Sunday". *)
+let test_to_string_names_the_source () =
+  let cases =
+    [ (MF.Proper, "proper"); (MF.Own_slug, "own"); (MF.Preceding_sunday, "preceding-sunday");
+      (MF.Common, "common") ]
+  in
+  List.iter
+    (fun (via, expected) ->
+      Alcotest.(check string) expected expected
+        (MF.source_to_string via))
+    cases
+
+let suite =
+  ( "Mass_formulary",
+    [ Alcotest.test_case "sexp round-trips" `Quick test_round_trips_through_sexp;
+      Alcotest.test_case "source_to_string names each source" `Quick
+        test_to_string_names_the_source ] )