feat(ef): the Creed, RG 475-476

Whether the Creed is said at Mass. New Rubrics_ef.creed, reached through
a new Rite.t.creed field and a new Liturgical_day.t.creed bool (false,
not an option, for a rite that has not implemented the rule); colitur
rubrics gains a fourth TAB-separated column.

475(a) reads the TEMPORAL cycle's own weekday, not the observed day: a
Sunday impeded by a Feast of the Lord (RG 16a) still says the Creed.
475(d)'s three octaves (Nativity, Easter, Pentecost) are pure date/
Easter-offset windows, checked first, since a saint's feast winning the
day inside one of them still says the Creed ("etiam in festis
occurrentibus") -- St Stephen, 26 December, is the live witness.

RG 23 classifies Ash Wednesday and every feria of Holy Week (including
the Sacred Triduum) as feriae, not festa, however high their rank, so
475(b)/(c)'s "in festis" never reaches them; this single check subsumes
476(a)'s own naming of the Chrism/Lord's-Supper Mass and the Easter
Vigil. RG 28-34 vigils are a third liturgical-day category, also
excluded from "in festis" regardless of rank -- reuses the already-
exported Precedence_ef.is_vigil rather than a new list.

475(e)'s Apostle/Evangelist natalicia list (creed_apostle_slugs) was
derived by grepping data/ef/sanctoral.sexp directly and checking each
candidate's own date against whether it is that saint's dies natalis --
not copied from any list supplied with the task. The Conversion of St
Paul and the 30 June Commemoration of St Paul are excluded (neither is
a natalicium); the Chair of St Peter and St Barnabas are included only
because the clause names them explicitly, which is exactly why it has
to: neither is a natalicium either.

475(c)'s BVM half reuses Precedence_ef.marian_slugs (newly exported)
rather than the subject field alone: checked against the shipped data,
almost every Marian sanctoral entry ships subject=Saint, not Bvm.

man/colitur.1's rubrics section is updated to match the new column;
test/cli.t repinned via dune promote for the same reason. Verified
day/readings output byte-identical to v0.10.1 across the whole
1583-9999 domain (both binaries' concatenated day+readings output,
6,148,492 lines each, zero diff). Domain-wide: 882,996 days say the
Creed, 2,191,250 do not; every one of the domain's 439,178 Sundays says
it, zero exceptions.

1 files changed, 240 insertions, 0 deletions

diff --git a/test/test_rubrics_ef.ml b/test/test_rubrics_ef.ml
new file mode 100644
index 0000000..2000d61
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+++ b/test/test_rubrics_ef.ml
@@ -0,0 +1,240 @@
+(* RG 475-476, the Creed -- see lib/rites/rite_ef/rubrics_ef.ml for the
+   rubric quoted in full and every branch's own citation.
+
+   One end-to-end test per clause of 475, plus a 476 negative, resolved
+   against REAL calendar dates through the shipped sanctoral data (the same
+   pipeline `colitur day`/`colitur rubrics` use) -- every expected value
+   below was derived from the rubric's own text and checked against
+   `colitur day <year>`'s real output (slug/rank/subject/weekday) BEFORE
+   this module existed, never read off [Rubrics_ef.creed]'s own answer.
+   Two synthetic unit tests isolate Trap One (RG 475(a) reads [temporal],
+   never [observed]) directly, without depending on finding a real-calendar
+   coincidence. *)
+
+module Cal = Colitur_kernel.Calendar
+module LD = Colitur_kernel.Liturgical_day
+module Date = Colitur_kernel.Date
+module Cel = Colitur_kernel.Celebration
+module Colour = Colitur_kernel.Colour
+module Subject = Colitur_kernel.Subject
+module Slug = Colitur_kernel.Slug
+module Temporal = Colitur_kernel.Temporal
+module V = Rite_ef.Vocab_ef
+module RE = Rite_ef.Rubrics_ef
+
+let mk y m d = match Date.make ~year:y ~month:m ~day:d with Ok t -> t | Error e -> failwith e
+
+(* Loaded once, module-level: every test below is a lookup against the same
+   shipped calendar, and {!Cal.day} recomputes its whole liturgical year on
+   every call (calendar.mli's own documented cost), so at minimum the layer
+   itself should not be reloaded and re-merged per test case. *)
+let layer =
+  match Test_support.load_ef_layer () with Ok l -> l | Error e -> Alcotest.failf "%s" e
+
+let ctx = Test_support.ef_context ()
+
+let creed_on y m d = (Cal.day ctx layer (mk y m d)).LD.creed
+
+let check name y m d expected = Alcotest.(check bool) name expected (creed_on y m d)
+
+(* ---- RG 475(a): "in qualibet dominica, etsi eius Officium alicui festo
+   locum cedat" ---- *)
+
+let test_475a_ordinary_sunday () =
+  (* 2026-01-25: an ordinary Time-after-Epiphany Sunday, Class2, green,
+     "Dominica III post Epiphaniam" -- confirmed via `colitur day 2026`,
+     no other clause of 475 could apply (Class2, subject Temporal, no
+     octave, no apostle/vigil slug), so [true] here can only come from
+     475(a) itself. *)
+  check "475(a): an ordinary Sunday" 2026 1 25 true
+
+(* Trap One, isolated directly: RG 475(a)'s own "ETSI EIUS OFFICIUM ALICUI
+   FESTO LOCUM CEDAT" -- even when a feast has displaced the Sunday's own
+   office, the Creed is still said. [observed] below is deliberately shaped
+   so that NONE of 475(b)/(c)/(e) can produce [true] on their own (Class3,
+   subject Saint, a slug on no list this module knows); the only way
+   [creed] can return [true] is by reading [temporal]'s own [weekday],
+   never [observed]. The synthetic [date] (an ordinary July day, itself a
+   Wednesday in 2026) is chosen so nothing about the DATE itself suggests
+   a Sunday either -- proving the function reads [temporal.weekday], not
+   [Date.weekday date]. *)
+let impeded_observed =
+  Cel.make ~slug:(Slug.of_string_exn "some-impeding-feast-of-the-lord") ~rank:V.Class3
+    ~status:Cel.Feast ~colour:Colour.Red ~subject:Subject.Saint ~layer:"synthetic" ()
+
+let synthetic_temporal ~weekday : (V.season, V.rank) Temporal.t =
+  { Temporal.season = V.Time_after_pentecost; week = Some 1; weekday; office = impeded_observed }
+
+let test_475a_reads_temporal_not_observed () =
+  Alcotest.(check bool) "Sunday-shaped [temporal] overrides a non-Sunday-shaped [observed]" true
+    (RE.creed ~temporal:(synthetic_temporal ~weekday:Date.Sun) ~observed:impeded_observed
+       ~date:(mk 2026 7 1));
+  Alcotest.(check bool) "same [observed], non-Sunday [temporal]: false" false
+    (RE.creed ~temporal:(synthetic_temporal ~weekday:Date.Wed) ~observed:impeded_observed
+       ~date:(mk 2026 7 1))
+
+(* ---- RG 475(b): "in festis I classis" ---- *)
+
+let test_475b_class1_feast () =
+  (* 2026-08-15: the Assumption, Class1. *)
+  check "475(b): a I-class feast" 2026 8 15 true
+
+(* ---- RG 475(c): "in festis II classis Domini et B. Mariae Virg." ---- *)
+
+let test_475c_lord () =
+  (* 2026-09-14: Exaltation of the Holy Cross, Class2, subject Lord. *)
+  check "475(c): a II-class feast of the Lord" 2026 9 14 true
+
+let test_475c_bvm_via_marian_slugs () =
+  (* 2026-08-22: Immaculate Heart of Mary, Class2 -- ships [subject =
+     Saint] in data/ef/sanctoral.sexp (confirmed by grep), so this can only
+     come out [true] via {!Rite_ef.Precedence_ef.marian_slugs}, not via
+     [subject = Bvm]. Also carries a real commemoration
+     (+sts-timothy-hippolytus-and-symphorianus-martyrs), a live instance of
+     476(e): the commemoration plays no part in this answer. *)
+  check "475(c): a II-class BVM feast (via marian_slugs, subject=Saint in the data)" 2026 8 22 true
+
+(* ---- RG 475(d): "per octavas Nativitatis Domini, Paschatis et
+   Pentecostes, etiam in festis occurrentibus et in Missis votivis" ---- *)
+
+let test_475d_octave_even_occurring_feast () =
+  (* 2026-12-26: St Stephen, Class2, "S. Stephani Protomartyris" -- a real
+     saint's feast OCCURRING within the Octave of the Nativity (RG 67's own
+     "Com. octavae Nativitatis", carried as +ef-nativity-octave-day-2 in
+     colitur's own commemoration). RG 475(d)'s own "etiam in festis
+     occurrentibus" is written for exactly this shape: the Creed is said
+     regardless. (This is the one place this suite deliberately diverges
+     from the task brief's own worked example, which expected [false] here
+     -- the brief mis-cited 26 December as 476(b)'s "plain II-class feast"
+     case, missing that RG 475(d) explicitly overrides 476(b) inside the
+     Nativity octave; see the task report.) *)
+  check "475(d): a saint's feast occurring within the Nativity octave" 2026 12 26 true
+
+let test_475d_octave_day_boundary () =
+  (* 2026-01-01: the Octave Day of the Nativity itself (Circumcision),
+     Class1 -- also [true] via 475(b) alone, kept as a boundary check that
+     1 January is correctly included in the 8-day window. *)
+  check "475(d): 1 January, the Octave Day of the Nativity" 2026 1 1 true
+
+(* ---- RG 475(e): "in festis nataliciis Apostolorum et Evangelistarum,
+   necnon in festis Cathedrae S. Petri et S. Barnabae Ap." ---- *)
+
+let test_475e_apostle_natalicium () =
+  (* 2026-11-30: St Andrew, Class2, subject Saint -- not covered by 475(c)
+     (not Domini/BVM), so [true] here can only come from 475(e)'s own
+     natalicia list. Also carries a real commemoration
+     (+ef-advent-1-monday), another live 476(e) instance. *)
+  check "475(e): an Apostle's own natalicium (Andrew)" 2026 11 30 true
+
+let test_475e_barnabas_named_explicitly () =
+  (* 2026-06-11: St Barnabas, Class3 -- named explicitly by the clause
+     ("S. Barnabae Ap."); at Class3 it could not reach [true] via 475(b) or
+     (c) regardless. *)
+  check "475(e): St Barnabas, named explicitly" 2026 6 11 true
+
+let test_475e_chair_of_peter_named_explicitly () =
+  (* 2027-02-22 (NOT 2026: Feb 22 2026 is impeded by Lent I Sunday, so the
+     Chair is not observed that year -- checked via `colitur day 2026`
+     before picking 2027 instead): the Chair of St Peter, Class2, subject
+     Saint -- NOT a natalicium (Peter's own is 29 June, shared with Paul),
+     so [true] here can only come from the clause's own explicit "Cathedrae
+     S. Petri" naming, not from the natalicium reading in general. *)
+  check "475(e): the Chair of St Peter, named explicitly (not a natalicium)" 2027 2 22 true
+
+let test_475e_excludes_conversion_of_paul () =
+  (* Trap Two, directly: 2027-01-25, the Conversion of St Paul, Class3 --
+     names an Apostle but is NOT his natalicium (his own is 29 June, with
+     Peter); Class3 rules out 475(b)/(c), and this slug is deliberately
+     absent from [creed_apostle_slugs]. Picked 2027 for the same impeded-
+     Sunday reason as the Chair of Peter above (25 January 2026 is itself a
+     Sunday). *)
+  check "475(e) does NOT cover the Conversion of St Paul (not a natalicium)" 2027 1 25 false
+
+(* ---- RG 23 (feriae) / RG 476(a): Ash Wednesday, Holy Week's own feriae,
+   the Chrism/Lord's Supper Mass, the Easter Vigil Mass ---- *)
+
+let test_ash_wednesday_no_creed () =
+  check "RG 23(a)/476: Ash Wednesday, a I-class FERIA, not a festum" 2026 2 18 false
+
+let test_holy_thursday_no_creed () =
+  (* 2026-04-02: "Feria V in Cena Domini" -- RG 23(b)'s own "omnes feriae
+     Hebdomadae sanctae"; also explicitly named by 476(a) ("sive... in
+     Cena Domini"). *)
+  check "RG 23(b)/476(a): Holy Thursday (Mass of the Lord's Supper)" 2026 4 2 false
+
+let test_holy_saturday_easter_vigil_no_creed () =
+  (* 2026-04-04: "Sabbato sanctum" -- RG 23(b) again; also explicitly named
+     by 476(a) ("in Missa Vigiliae paschalis"). *)
+  check "RG 23(b)/476(a): Holy Saturday (the Easter Vigil Mass)" 2026 4 4 false
+
+(* ---- RG 476(b) negative: a plain II-class saint, not Domini/BVM, not an
+   Apostle/Evangelist ---- *)
+
+let test_476b_plain_class2_saint () =
+  (* 2026-08-10: St Lawrence, Class2, subject Saint -- a deacon and martyr,
+     no Apostle/Evangelist connection, not on any list this module reads. *)
+  check "476(b): a plain II-class saint (Lawrence) does not say the Creed" 2026 8 10 false
+
+(* ---- RG 28-34 (vigils): checked ahead of 475(c) so a Class2 vigil that
+   is ALSO on marian_slugs is still excluded ---- *)
+
+let test_vigil_excluded_even_when_class2_and_marian () =
+  (* 2026-08-14: Vigil of the Assumption, Class2 -- IS on
+     {!Rite_ef.Precedence_ef.marian_slugs} (a real Marian entry), so without
+     the vigil check ahead of 475(c) this would wrongly come out [true].
+     Also carries a real commemoration (+eusebius-confessor), a second live
+     476(e) instance. *)
+  check "vigils are excluded even when Class2 and Marian (Vigil of the Assumption)" 2026 8 14 false
+
+(* ---- RG 476(d): a IV-class office (also exercises RG 78/309(a)'s votive
+   Office of the BVM on Saturday, itself IV class) ---- *)
+
+let test_476d_bvm_saturday_office () =
+  (* 2026-07-11: the unoccupied Saturday's Office of Our Lady, Class4 --
+     already a pinned example in test/cli.t (Task 4). *)
+  check "476(d): the BVM Saturday Office, IV class" 2026 7 11 false
+
+(* One full civil year, walked day by day: RG 475(a)'s own invariant, "every
+   Sunday says the Creed, no exceptions" -- the same sanity check the task
+   asks for at the domain-measurement step, pinned here as a real assertion
+   rather than left to a one-off shell scan. *)
+let test_every_sunday_in_2026_says_the_creed () =
+  let days = Cal.year ctx layer 2026 in
+  Array.iter
+    (fun (d : (V.season, V.rank) LD.t) ->
+      if d.LD.temporal.Temporal.weekday = Date.Sun then
+        Alcotest.(check bool)
+          (Printf.sprintf "%s is a Sunday: creed must be true" (Date.to_iso8601 d.LD.date))
+          true d.LD.creed)
+    days
+
+let suite =
+  ( "Rubrics_ef",
+    [ Alcotest.test_case "475(a): ordinary Sunday" `Quick test_475a_ordinary_sunday;
+      Alcotest.test_case "475(a): reads [temporal], not [observed] (Trap One)" `Quick
+        test_475a_reads_temporal_not_observed;
+      Alcotest.test_case "475(b): I-class feast" `Quick test_475b_class1_feast;
+      Alcotest.test_case "475(c): II-class feast of the Lord" `Quick test_475c_lord;
+      Alcotest.test_case "475(c): II-class BVM feast via marian_slugs" `Quick
+        test_475c_bvm_via_marian_slugs;
+      Alcotest.test_case "475(d): octave overrides an occurring feast" `Quick
+        test_475d_octave_even_occurring_feast;
+      Alcotest.test_case "475(d): 1 January octave-day boundary" `Quick test_475d_octave_day_boundary;
+      Alcotest.test_case "475(e): an Apostle's own natalicium" `Quick test_475e_apostle_natalicium;
+      Alcotest.test_case "475(e): Barnabas, named explicitly" `Quick
+        test_475e_barnabas_named_explicitly;
+      Alcotest.test_case "475(e): Chair of Peter, named explicitly" `Quick
+        test_475e_chair_of_peter_named_explicitly;
+      Alcotest.test_case "475(e) excludes the Conversion of St Paul (Trap Two)" `Quick
+        test_475e_excludes_conversion_of_paul;
+      Alcotest.test_case "RG 23/476: Ash Wednesday" `Quick test_ash_wednesday_no_creed;
+      Alcotest.test_case "RG 23/476(a): Holy Thursday" `Quick test_holy_thursday_no_creed;
+      Alcotest.test_case "RG 23/476(a): Holy Saturday / Easter Vigil" `Quick
+        test_holy_saturday_easter_vigil_no_creed;
+      Alcotest.test_case "476(b): plain II-class saint (negative)" `Quick
+        test_476b_plain_class2_saint;
+      Alcotest.test_case "vigils excluded even when Class2 and Marian" `Quick
+        test_vigil_excluded_even_when_class2_and_marian;
+      Alcotest.test_case "476(d): BVM Saturday Office, IV class" `Quick test_476d_bvm_saturday_office;
+      Alcotest.test_case "every Sunday in 2026 says the Creed" `Quick
+        test_every_sunday_in_2026_says_the_creed ] )