test(ef): pin the overlay suppression's own observable effect

With data/ef/adjustments.sexp's one Suppress directive replaced by an
empty directive list, colitur day 2026's stdout was byte-identical for
all 365 days and the whole suite still passed: ef-nativity-vigil already
outranks vigil-of-christmas in the RG91 contest regardless of whether
the overlay ever ran, so the suppression's only observable effect is
keeping vigil-of-christmas out of 24 December's Liturgical_day.omitted
-- a field no cram assertion reads. test/dune's own dep on
adjustments.sexp pinned the file's existence, never its content.

Confirmed the gap two ways: reverting the overlay to (directives ())
makes this new test fail (24 December's omitted gains
vigil-of-christmas), and confirmed test/cli.t's whole cram suite still
passes under that same mutation -- cram is structurally blind to this,
not merely undertested.

1 files changed, 48 insertions, 2 deletions

diff --git a/test/test_rite_ef.ml b/test/test_rite_ef.ml
index 7b60718..bfc97dc 100644
--- a/test/test_rite_ef.ml
+++ b/test/test_rite_ef.ml
@@ -1,7 +1,13 @@
 (* Coordinator review (Task 11 fix round): integration tests wiring
    [Rite_ef.context] together with the REAL data/ef/sanctoral.sexp +
    data/ef/adjustments.sexp through [Colitur_kernel.Calendar] -- the same
-   pipeline `colitur day` uses, proven here at the OCaml level. *)
+   pipeline `colitur day` uses, proven here at the OCaml level so these
+   properties are pinned by the test suite, not merely observable in CLI
+   output (which is exactly what finding 3 flagged: with the overlay's one
+   directive replaced by [()], `colitur day 2026`'s stdout is byte-identical
+   for all 365 days, since [ef-nativity-vigil] always outranks
+   [vigil-of-christmas] regardless -- the suppression's only observable
+   effect is on [Liturgical_day.omitted], which no cram assertion reads). *)
 
 module Cal = Colitur_kernel.Calendar
 module Layer = Colitur_kernel.Layer
@@ -20,6 +26,8 @@ module V = Rite_ef.Vocab_ef
 let sanctoral_path = "../data/ef/sanctoral.sexp"
 let adjustments_path = "../data/ef/adjustments.sexp"
 
+let mk y m d = match Date.make ~year:y ~month:m ~day:d with Ok t -> t | Error e -> failwith e
+
 let real_layer () =
   let layer =
     match Layer.load V.rank_of_sexp sanctoral_path with
@@ -38,6 +46,42 @@ let real_layer () =
 
 let slug_of (c : V.rank Cel.t) = Slug.to_string c.Cel.slug
 
+(* Finding 3: the suppression's ONLY observable effect is on 24 December's
+   [omitted] (and, belt-and-braces, on every OTHER field of every OTHER day
+   too -- vigil-of-christmas must not surface anywhere at all, since the
+   overlay removes it from the layer before resolution ever runs, unlike an
+   ordinary occurrence loss). Mutation-verified (see the task report):
+   substituting `(directives ())` for the real overlay makes this test's
+   first assertion fail (24 December's [omitted] gains
+   "vigil-of-christmas"), and confirmed the whole cram suite (test/cli.t)
+   still passes under that same mutation -- so this closes the "removing
+   the deliverable breaks no test" gap the coordinator flagged, which cram
+   alone structurally cannot. *)
+let test_vigil_of_christmas_suppressed () =
+  let layer = real_layer () in
+  let days = Cal.year Rite_ef.context layer 2026 in
+  let christmas_eve =
+    Array.to_list days |> List.find (fun d -> Date.compare d.LD.date (mk 2026 12 24) = 0)
+  in
+  Alcotest.(check string) "ef-nativity-vigil is still the observed day" "ef-nativity-vigil"
+    (slug_of christmas_eve.LD.observed);
+  Alcotest.(check (list string))
+    "24 December has nothing omitted -- vigil-of-christmas never enters the RG91 contest at all"
+    []
+    (List.map (fun (c, _) -> slug_of c) christmas_eve.LD.omitted);
+  let appears_anywhere =
+    Array.to_list days
+    |> List.exists (fun d ->
+           let is_it c = slug_of c = "vigil-of-christmas" in
+           is_it d.LD.observed
+           || List.exists (fun (c, _) -> is_it c) d.LD.commemorations
+           || List.exists (fun (c, _) -> is_it c) d.LD.omitted
+           || (match d.LD.transferred_in with Some c -> is_it c | None -> false)
+           || List.exists (fun (c, _) -> is_it c) d.LD.transferred_out)
+  in
+  Alcotest.(check bool) "vigil-of-christmas appears NOWHERE in the resolved year" false
+    appears_anywhere
+
 (* Coordinator review, finding 2, reproduced through the project's OWN
    extension path (an overlay), the same way the reviewer found it: adding
    an I-class feast on 25 December (competing against, and losing to, the
@@ -77,5 +121,7 @@ let test_transfer_search_does_not_raise_at_domain_ceiling () =
 
 let suite =
   ( "Rite_ef (real data: overlay-in-effect, domain-ceiling)",
-    [ Alcotest.test_case "RG96 search does not raise at the domain ceiling (real data)" `Quick
+    [ Alcotest.test_case "the overlay suppression is observably in effect" `Quick
+        test_vigil_of_christmas_suppressed;
+      Alcotest.test_case "RG96 search does not raise at the domain ceiling (real data)" `Quick
         test_transfer_search_does_not_raise_at_domain_ceiling ] )