test(ef): reach RG 91 entry 27 through the real pipeline, end-to-end

Entry 27's band branch has been unreachable for the right reason since
it was written: precedence_ef.ml's own comment on it acknowledged the
row existed, but the one test exercising it built a hand-typed
candidate, never a real Temporal_ef.temporal output, and nothing built
the office itself. Closes that gap on both sides:

- The band-table row now sources its candidate from Temporal_ef.temporal
  directly (of_temporal), the same review-finding-3 discipline the
  Ember/vigil rows already use, so a future regression in the office's
  own construction fails this row too, not only the unit-level test.
- Two new resolve-level end-to-end tests, using the real band/
  disposition/admit triple (not stubs): the office winning a real
  otherwise-unoccupied Saturday and admitting an ordinary commemoration
  alongside it (1 August 2026, Holy Machabees -- the task brief's own
  worked oracle example), and the office genuinely losing to a real
  competing feast and being omitted under RG 26, with no confusion from
  the one live data witness that also carries subject Bvm (12 September,
  Most Holy Name of Mary) -- proving RG 26's rank-keyed omission fires
  before any subject-keyed rule ever could.
- Two golden pins mirroring the same two dates, checked by hand against
  `colitur day 2026` before being typed in, following this file's own
  "a golden test blesses whatever it is given, verified independently"
  discipline. The existing 2038-03-06 pin (RG 91 entry 24 outranking a
  Class4 candidate) is corrected in passing: that date is itself a
  Saturday, so the displaced candidate the pin's own omitted-list check
  names is now precisely entry 27's own shape, not entry 28's bare
  catch-all -- the win/lose outcome the pin proves is unchanged, only
  its own more precise citation.

Mutation-tested (recorded in the task report): reverting
is_bvm_saturday to a constant false reddens the dedicated unit test, the
new end-to-end resolve test, and the 2026-08-01 golden pin, while
leaving the 2026-09-12 "loses to a real feast" pin untouched, exactly as
expected since that date's outcome never depended on the fix.

1 files changed, 98 insertions, 4 deletions

diff --git a/test/test_precedence_ef.ml b/test/test_precedence_ef.ml
index ed9a933..475ae6e 100644
--- a/test/test_precedence_ef.ml
+++ b/test/test_precedence_ef.ml
@@ -291,10 +291,21 @@ let cases =
       cand ~origin:P.Sanctoral ~rank:V.Class3 ~layer:PE.universal_layer "vigil-of-st-lawrence",
       260 );
     (* Entry 27 -- RG 91 entry 27 (§4): an otherwise-unoccupied IV-class
-       Saturday. *)
-    ( "27 Office of the BVM on Saturday", off 62,
-      cand ~rank:V.Class4 "ef-time-after-pentecost-1-sat",
-      270 );
+       Saturday. ef-bvm-saturday task: sourced from [Temporal_ef.temporal]'s
+       own real output (see [of_temporal], the same review-finding-3
+       discipline entry 18's/21's own rows above use), not a hand-typed
+       slug/rank pair -- this row used to be the one place in this whole
+       suite where [band]'s entry-27 branch was exercised by a value nothing
+       in [Temporal_ef.temporal] could actually produce (the office itself
+       was unbuilt): [band] read [rank = Class4 && weekday = Sat]
+       correctly, but nothing proved [temporal] ever handed it a candidate
+       shaped that way for the RIGHT reason. Now it does: [of_temporal (off
+       62)] is 6 June 2026, a real otherwise-contested Time-after-Pentecost
+       Saturday (Norbert, Class3, wins the DAY outright in the real
+       pipeline -- irrelevant here, since this row tests [band] on the
+       TEMPORAL CANDIDATE alone, which [Temporal_ef.temporal] builds as the
+       BVM Saturday office regardless of what wins). *)
+    ( "27 Office of the BVM on Saturday (from Temporal_ef.temporal)", off 62, of_temporal (off 62), 270 );
     (* Entry 28 -- RG 91 entry 28 (§4): the unqualified IV-class catch-all. *)
     ("28 IV-class feria", off 65, cand ~rank:V.Class4 "ef-time-after-pentecost-1-tue", 280);
     (* Not an RG 91 row at all: a I-class candidate marked as a vigil, which
@@ -1421,6 +1432,81 @@ let test_ii_class_sunday_privileged_witness_admitted_end_to_end () =
     [ ("ef-some-saint", "omitted: admission limit reached") ]
     (List.map (fun (c, reason) -> (S.to_string c.P.cel.Cel.slug, reason)) resolution.P.omitted)
 
+(* RG 91 entry 27 / RG 78-79 (Caput IX, "De sancta Maria in sabbato") reached
+   end-to-end through the REAL pipeline -- this is THE hazard this task's own
+   brief names explicitly: {!PE.band}'s entry-27 branch has been reachable
+   only in isolation (the table-driven row above) since it was written, never
+   through a real [Temporal_ef.temporal] candidate winning an actual day, so
+   this test is checked for whether it exercises entry 27 for the RIGHT
+   reason -- proved by the mutation test recorded in the task report
+   (reverting temporal_ef.ml's own [is_bvm_saturday] branches back to the
+   generic ferial fallback reddens THIS test, not merely the [band]-table
+   row, which would still pass unchanged since it is sourced from real
+   [T.temporal] output either way).
+
+   1 August 2026, matching the task brief's own worked example against the
+   oracle exactly: a Time-after-Pentecost Saturday, otherwise unoccupied but
+   for Holy Machabees (Commemoration_only, Class3, real data/ef/sanctoral.sexp
+   entry, 1 August) -- the office wins outright (band 270, ahead of Holy
+   Machabees's own [unclassified]) and the Commemoration_only loser still
+   rides along as an ordinary commemoration, the SAME shape the oracle's own
+   row for this date shows ("V Mass of the B. V. M. -- Salve, Sancta Parens",
+   commemorating Holy Machabees). *)
+let test_bvm_saturday_wins_and_commemorates_end_to_end () =
+  let date = mk 2026 8 1 in
+  let day_ctx = ctx date in
+  let bvm_saturday = of_temporal date in
+  let holy_machabees =
+    cand ~origin:P.Sanctoral ~rank:V.Class3 ~status:Cel.Commemoration_only ~layer:PE.universal_layer
+      "holy-machabees"
+  in
+  let resolution = P.resolve real_rules day_ctx ~temporal:bvm_saturday ~sanctoral:[ holy_machabees ] in
+  Alcotest.(check string) "the BVM Saturday office is observed, not Holy Machabees"
+    "ef-time-after-pentecost-9-saturday" (S.to_string resolution.P.observed.P.cel.Cel.slug);
+  Alcotest.(check string) "observed rank is class-4, unconditional" "class-4"
+    (V.rank_to_string resolution.P.observed.P.cel.Cel.rank);
+  Alcotest.(check string) "observed colour is white, overriding the season's own green" "white"
+    (Col.to_string resolution.P.observed.P.cel.Cel.colour);
+  Alcotest.(check bool) "observed subject is Bvm" true (resolution.P.observed.P.cel.Cel.subject = Sub.Bvm);
+  Alcotest.(check (list (pair string string))) "Holy Machabees still rides along as an ordinary commemoration"
+    [ ("holy-machabees", "Ordinary") ]
+    (List.map
+       (fun (c, p) -> (S.to_string c.P.cel.Cel.slug, match p with P.Privileged -> "Privileged" | P.Ordinary -> "Ordinary"))
+       resolution.P.commemorations);
+  Alcotest.(check int) "nothing omitted" 0 (List.length resolution.P.omitted)
+
+(* The other half of the SAME hazard: a real Saturday where RG 78's own
+   protasis is FALSE (a genuine sanctoral feast wins the day outright), so
+   the BVM-Saturday-shaped temporal candidate must lose, and be OMITTED under
+   RG 26 (a temporal Class4 non-vigil loser is never commemorated) exactly
+   like the plain ferial candidate it replaces always was -- proving [band]/
+   [disposition] need no special case for this office at all, the design
+   claim the task report makes explicitly. 12 September 2026 is a Saturday
+   where `most-holy-name-of-mary` (data/ef/adjustments.sexp's own [Set_subject
+   Bvm] entry, Class3 Feast) wins outright -- ALSO tagged [subject = Bvm],
+   the one live data witness that could in principle confuse a
+   subject-keyed disposition rule with RG 26's own rank-keyed one: this test
+   proves they do NOT collide (RG 26 fires first, unconditionally, on the
+   loser's own [rank = Class4], never reaching a subject comparison at all). *)
+let test_bvm_saturday_loses_to_a_real_feast_end_to_end () =
+  let date = mk 2026 9 12 in
+  let day_ctx = ctx date in
+  let bvm_saturday = of_temporal date in
+  let name_of_mary =
+    cand ~origin:P.Sanctoral ~rank:V.Class3 ~subject:Sub.Bvm ~layer:PE.universal_layer
+      "most-holy-name-of-mary"
+  in
+  let resolution = P.resolve real_rules day_ctx ~temporal:bvm_saturday ~sanctoral:[ name_of_mary ] in
+  Alcotest.(check string) "Most Holy Name of Mary is observed, not the BVM Saturday office"
+    "most-holy-name-of-mary" (S.to_string resolution.P.observed.P.cel.Cel.slug);
+  Alcotest.(check (list string)) "nothing is commemorated" []
+    (List.map (fun (c, _) -> S.to_string c.P.cel.Cel.slug) resolution.P.commemorations);
+  Alcotest.(check (list (pair string string)))
+    "the BVM-Saturday-shaped temporal candidate is omitted under RG26, not commemorated -- no Bvm-vs-Bvm \
+     confusion with RG112(a)-style subject logic"
+    [ ("ef-time-after-pentecost-15-saturday", "omitted: yielded to a higher day") ]
+    (List.map (fun (c, reason) -> (S.to_string c.P.cel.Cel.slug, reason)) resolution.P.omitted)
+
 (* RG 16(a) (register §6.0) reached end-to-end through the REAL pipeline
    ([PE.band], [PE.disposition] AND [PE.admit] together, not any one of
    them in isolation as this file's own hand-tagged rows test them
@@ -1895,6 +1981,14 @@ let suite =
           "II-class Sunday override: RG109(b) witness admitted over an ordinary saint, end-to-end"
           `Quick test_ii_class_sunday_privileged_witness_admitted_end_to_end;
         Alcotest.test_case
+          "RG91 e27/RG78: the BVM Saturday office wins and commemorates Holy Machabees, end-to-end \
+           (2026-08-01)"
+          `Quick test_bvm_saturday_wins_and_commemorates_end_to_end;
+        Alcotest.test_case
+          "RG91 e27/RG78/RG26: the BVM Saturday office loses to a real feast and is omitted, end-to-end \
+           (2026-09-12)"
+          `Quick test_bvm_saturday_loses_to_a_real_feast_end_to_end;
+        Alcotest.test_case
           "RG16(a): a Feast of the Lord suppresses the Sunday's own commemoration entirely, \
            end-to-end (2028-08-06)"
           `Quick test_rg16a_lord_feast_suppresses_sunday_end_to_end;