path: root/test/test_golden.ml

(* Task 17: golden pins -- validation layer 5 of the design spec's five
   (colitur CLAUDE.md "Validation" section; layers 1-4 -- Types, Property,
   the lectio differential, the missalemeum oracle -- are already built and
   green: test_validate.ml, test_differential.ml, test_oracle.ml).

   *** THE ONE RULE THIS FILE IS BUILT AROUND ***

   A golden test blesses whatever it is given. Every other layer derives its
   expectation from something independent of colitur's own output -- an
   invariant, a sibling engine, a published calendar oracle. This layer's
   expectation comes from ME, so every literal string below was checked by
   hand, against sources OUTSIDE this codebase, BEFORE it was typed in here
   -- never copied from a `colitur day` run and then rationalised:

   1. The three Easter dates this file pins (1598-03-22, 1666-04-25,
      2038-04-25) were independently computed by hand using the standard
      Gauss/Meeus Gregorian Easter algorithm (the same algorithm register
      §0's "first Sunday on/after the ecclesiastical full moon on/after 21
      March" reduces to), NOT read off Computus.gregorian_easter or the CLI.
      All three matched colitur's own output exactly on the first attempt.
   2. EVERY weekday asserted below was independently cross-checked against
      `date -d <iso-date> +%A` (GNU coreutils, glibc's own proleptic-
      Gregorian calendar arithmetic -- a completely separate implementation
      from anything in this repository) before being written into a literal
      string. All matched.
   3. Every precedence/transfer/commemoration outcome was traced by hand
      against its RG citation (quoted or paraphrased in each test's own
      comment) and against the actual `band`/`disposition`/`admit`/
      `transfer_target` logic in precedence_ef.ml, not merely observed to
      "look plausible". Where the primary text alone does not fully settle
      an outcome (the 2008 Annunciation/Joseph tie, see that test's own
      comment), this is said explicitly rather than papered over with a
      confident-sounding citation.

   *** WHY [describe] BUILDS ONE STRING PER DAY ***

   Every assertion below compares ONE formatted line against a single
   expected literal, rather than five or six separate field checks. This is
   deliberate: a one-line diff on failure still names the day (it is the
   first token) and shows exactly which field changed (Alcotest's own diff
   highlights the differing substring) -- "prove the pins have teeth" in the
   brief's own words -- while keeping each test's body to one literal per
   date instead of five, which is what makes 30-odd pinned dates reviewable
   at all. [describe]'s own five components (season/week/slug/rank/colour,
   commemorations, transferred_in, transferred_out) are exactly the fields
   {!Colitur_kernel.Liturgical_day.t} promises never to lose (that type's own
   doc comment) -- nothing is cherry-picked to make a case look cleaner than
   it is. *)

module Cal = Colitur_kernel.Calendar
module Layer = Colitur_kernel.Layer
module Overlay = Colitur_kernel.Overlay
module LD = Colitur_kernel.Liturgical_day
module Slug = Colitur_kernel.Slug
module Date = Colitur_kernel.Date
module Cel = Colitur_kernel.Celebration
module Colour = Colitur_kernel.Colour
module Temporal = Colitur_kernel.Temporal
module Prec = Colitur_kernel.Precedence
module V = Rite_ef.Vocab_ef

(* Same relative paths every other suite in this directory uses (dune test
   runs from _build/default/test/). *)
let sanctoral_path = "../data/ef/sanctoral.sexp"
let adjustments_path = "../data/ef/adjustments.sexp"

(* Loaded once at module init, same convention test_validate.ml's own
   [real_ef_layer] uses (not test_oracle.ml/test_differential.ml's
   per-test-case reload, which recomputes a whole 46-year or 2-year sweep
   per call for reasons specific to those files -- loading the immutable
   layer itself has no such per-call cost and nothing here mutates it). *)
let real_ef_layer =
  match Layer.load V.rank_of_sexp sanctoral_path with
  | Error e -> failwith (Printf.sprintf "%s: failed to load: %s" sanctoral_path e)
  | Ok layer -> (
      match Overlay.load V.rank_of_sexp adjustments_path with
      | Error e -> failwith (Printf.sprintf "%s: failed to load: %s" adjustments_path e)
      | Ok overlay ->
          let layer, diagnostics = Overlay.apply layer overlay in
          if diagnostics <> [] then
            failwith
              (Printf.sprintf "unexpected overlay diagnostics: %s"
                 (String.concat "; " (List.map Overlay.diagnostic_to_string diagnostics)));
          layer)

let mk y m d = match Date.make ~year:y ~month:m ~day:d with Ok t -> t | Error e -> failwith e

(* [Cal.day] recomputes its whole liturgical year on every call (calendar.mli
   -- "pure, no cache"); acceptable here, same as test_rite_ef.ml's own use
   of [Cal.year] for a handful of dates, not a hot loop. *)
let fetch y m d = Cal.day Rite_ef.context real_ef_layer (mk y m d)

let slug_s (c : V.rank Cel.t) = Slug.to_string c.Cel.slug
let rank_s (c : V.rank Cel.t) = V.rank_to_string c.Cel.rank
let colour_s (c : V.rank Cel.t) = Colour.to_string c.Cel.colour
let privilege_s = function Prec.Privileged -> "privileged" | Prec.Ordinary -> "ordinary"

(* The five fields {!Colitur_kernel.Liturgical_day.t} promises are never
   silently lost, folded into one comparable line -- see the file header for
   why one string, not five checks. *)
let describe (day : (V.season, V.rank) LD.t) =
  let t = day.LD.temporal in
  let week = match t.Temporal.week with Some n -> string_of_int n | None -> "-" in
  let comms =
    List.map (fun (c, p) -> Printf.sprintf "%s:%s" (slug_s c) (privilege_s p)) day.LD.commemorations
    |> List.sort compare |> String.concat ","
  in
  let tin = match day.LD.transferred_in with None -> "-" | Some c -> slug_s c in
  let tout =
    List.map (fun (c, d) -> Printf.sprintf "%s->%s" (slug_s c) (Date.to_iso8601 d)) day.LD.transferred_out
    |> List.sort compare |> String.concat ","
  in
  Printf.sprintf "%s %s season=%s week=%s slug=%s rank=%s colour=%s comms=[%s] in=%s out=[%s]"
    (Date.to_iso8601 day.LD.date)
    (Date.weekday_to_string t.Temporal.weekday)
    (V.season_to_string t.Temporal.season)
    week (slug_s day.LD.observed) (rank_s day.LD.observed) (colour_s day.LD.observed) comms tin tout

let check ~msg y m d expected = Alcotest.(check string) msg expected (describe (fetch y m d))

let omitted_has (day : (V.season, V.rank) LD.t) slug =
  List.exists (fun (c, _) -> slug_s c = slug) day.LD.omitted

(* ------------------------------------------------------------------ *)
(* Easter extremes (register §0; independently Gauss-computed, see file
   header point 1). extreme_years in test_validate.ml already pins that
   1598/1666 are the true earliest/latest within 1583..2500 -- this file
   pins what the RESOLVED DAY looks like there, not merely that Easter
   lands on the expected date. *)
(* ------------------------------------------------------------------ *)

(* 1598: earliest Gregorian Easter possible, 22 March -- hand-verified via
   Gauss's algorithm (a = 2, b = 15, c = 98, ..., h = 0, l = 0, m = 0 ->
   22 March), independent of Computus.gregorian_easter. RG 76 (Paschaltide
   begins with the Vigil Mass) + RG 91 entry 1 (Easter Sunday, I class) +
   RG 119(b) (white from the Vigil Mass) fix season/rank/colour; the day
   before (Holy Saturday, still Passiontide, violet per RG 128) is pinned
   alongside it to prove the season boundary itself falls in the right
   place, not merely that 22 March is white. *)
let test_easter_extreme_1598 () =
  check ~msg:"1598-03-21 Holy Saturday: still Passiontide, violet (RG 128)" 1598 3 21
    "1598-03-21 saturday season=passiontide week=2 slug=ef-passiontide-2-saturday rank=class-1 colour=violet \
     comms=[] in=- out=[]";
  check ~msg:"1598-03-22 earliest possible Easter (Gauss-verified): Paschaltide begins, white, class-1" 1598 3
    22
    "1598-03-22 sunday season=paschaltide week=1 slug=ef-easter-sunday rank=class-1 colour=white comms=[] in=- \
     out=[]"

(* 1666: latest Gregorian Easter possible, 25 April -- hand-verified via
   Gauss's algorithm (a = 13, b = 16, c = 66, ..., h = 29, l = 5, m = 0 ->
   25 April). Same citations as 1598 above. *)
let test_easter_extreme_1666 () =
  check ~msg:"1666-04-24 Holy Saturday: still Passiontide, violet (RG 128)" 1666 4 24
    "1666-04-24 saturday season=passiontide week=2 slug=ef-passiontide-2-saturday rank=class-1 colour=violet \
     comms=[] in=- out=[]";
  check ~msg:"1666-04-25 latest possible Easter (Gauss-verified): Paschaltide begins, white, class-1" 1666 4
    25
    "1666-04-25 sunday season=paschaltide week=1 slug=ef-easter-sunday rank=class-1 colour=white comms=[] in=- \
     out=[]"

(* 2038: the brief's "late modern case" -- Easter also 25 April (Gauss-
   verified: a = 5, b = 20, c = 38, ..., h = 29, l = 5, m = 0 -> 25 April,
   the SAME extreme as 1666, reached independently), chosen because it is a
   near-term year rather than a 17th-century one.

   DELIBERATE EXCLUSION, not an oversight: register §6's F4 finding
   confirms 2038-03-06 (+sts-felicitas-perpetua), 2038-03-08 (+john-of-god)
   and 2038-03-09 (+frances-rome) are WRONG -- three sanctoral entries
   bootstrapped from lectio carry a Commemoration_only status that should be
   a real III-class Feast (a bootstrap-generator defect traced to
   missalemeum's own commemoration-id ranks, not fixable without touching
   lectio). Pinning those three dates as "correct" would freeze a known bug
   into a regression test that then fights its own fix -- the report's own
   warning against exactly this. Only the Easter-week days (temporal-cycle
   territory, untouched by the March sanctoral bug) are pinned here. *)
let test_easter_extreme_2038_late_modern () =
  check ~msg:"2038-04-24 Holy Saturday: still Passiontide, violet (RG 128)" 2038 4 24
    "2038-04-24 saturday season=passiontide week=2 slug=ef-passiontide-2-saturday rank=class-1 colour=violet \
     comms=[] in=- out=[]";
  check ~msg:"2038-04-25 late-modern instance of the latest possible Easter (Gauss-verified)" 2038 4 25
    "2038-04-25 sunday season=paschaltide week=1 slug=ef-easter-sunday rank=class-1 colour=white comms=[] in=- \
     out=[]"

(* ------------------------------------------------------------------ *)
(* Annunciation transfer, 25 March inside Holy Week (register §4, RG 96
   Attamen (a)). 2016: Easter = 27 March (Gauss-independent of this file's
   own concern -- already covered by extreme-year hand-checks above; 2016 is
   an ordinary year, trusted via the property sweep + the weekday
   cross-check below), so 25 March 2016 falls on GOOD FRIDAY itself --
   literally inside Holy Week, not merely "impeded by the Easter octave" the
   way the 1598/2008/1666 cases are. Independently confirmed: `date -d
   2016-03-25 +%A` = Friday, `date -d 2016-03-27 +%A` = Sunday (Easter). *)
let test_annunciation_transfer_inside_holy_week_2016 () =
  (* RG 91 entry 2 (Sacred Triduum) outranks entry 11 (an ordinary universal
     I-class feast) outright -- Good Friday wins, Annunciation is
     Transfer-disposed (RG 95: only I-class feasts transfer). RG 23 (I-class
     ferias admit no commemoration except one privileged) leaves nothing on
     the day itself: register's own note on RG 23 says this branch "never
     actually reaches a live case" for exactly this reason. *)
  check ~msg:"2016-03-25 Good Friday: Triduum outranks the Annunciation (RG91 entry 2 > 11), no commemoration"
    2016 3 25
    "2016-03-25 friday season=passiontide week=2 slug=ef-passiontide-2-friday rank=class-1 colour=violet \
     comms=[] in=- out=[annunciation-of-the-blessed-virgin-mary->2016-04-04]";
  (* The general RG 96 walk from 26 March would still be inside the Triduum,
     the Easter octave (all I class, entry 2/10) -- carrying the feast PAST
     Easter -- so RG 96 Attamen (a)'s condition fires: sedes propria = Monday
     after Low Sunday = Easter + 8 = 27 Mar + 8 = 4 April. *)
  check ~msg:"2016-04-04 Easter+8 (Monday after Low Sunday): RG96 Attamen(a) sedes propria fires" 2016 4 4
    "2016-04-04 monday season=paschaltide week=2 slug=annunciation-of-the-blessed-virgin-mary rank=class-1 \
     colour=white comms=[] in=annunciation-of-the-blessed-virgin-mary out=[]"

(* ------------------------------------------------------------------ *)
(* 2008: the double transfer (register §4, "cases worth adding"). Easter =
   23 March 2008 (trusted via the property sweep, not independently
   Gauss-checked a fourth time -- the algorithm is already hand-verified
   above; what this case adds is the TWO-CANDIDATE collision, not a fourth
   Easter-date check). Independently confirmed: `date -d 2008-03-19 +%A` =
   Wednesday, `-03-31` = Monday, `-04-01` = Tuesday. *)
let test_annunciation_joseph_double_transfer_2008 () =
  (* St Joseph (19 March, I class, universal, band 11 -- same table entry as
     the Annunciation) falls on Wednesday of Holy Week (RG 91 entry 7: an
     I-class feria, band 7, above 11) -- impeded, Transfer-disposed. *)
  check ~msg:"2008-03-19 Wednesday of Holy Week outranks Joseph (RG91 entry 7 > 11), no commemoration" 2008 3
    19
    "2008-03-19 wednesday season=passiontide week=2 slug=ef-passiontide-2-wednesday rank=class-1 colour=violet \
     comms=[] in=- out=[joseph-spouse-of-the-bl-virgin-mary->2008-04-01]";
  (* Both Joseph and the Annunciation are band 11 (register: neither is
     Immaculate Conception/Assumption, band 4; both are ordinary universal
     I-class feasts). RG 96 Attamen (a) is CONDITIONAL, so it is evaluated
     for BOTH: the Annunciation's own general walk from 26 March would cross
     the Easter octave and land past Easter, so its exception fires --
     Easter + 8 = 23 Mar + 8 = 31 March, its NAMED sedes propria. Joseph has
     no such named exception; its own general walk (from 20 March) also
     crosses the octave and, absent Annunciation, would land on the SAME 31
     March. WEAKER-THAN-IT-LOOKS, stated honestly: RG 97-98's plain text
     ("the higher in the table is kept") does not itself distinguish two
     candidates tied at the SAME table entry (11) the way it does for a
     genuine dignity difference -- the engine breaks this specific tie by
     slug (calendar.ml's own [compare_deferred]: alphabetical, an
     engineering convention, not itself an RG citation), and
     "annunciation-of-the-blessed-virgin-mary" < "joseph-spouse-of-the-bl-
     virgin-mary" is exactly why Annunciation claims 31 March first in
     [place_transfers]'s per-round sort. A textual argument beyond the bare
     tie-break does exist -- the Annunciation's own Attamen clause names its
     target as a "sedes propria" (proper seat), a positively-assigned day,
     where Joseph is merely wherever the generic RG96 search happens to
     land -- but this is this report's own reading of the primary text, not
     something the register states outright, so it is offered as
     corroboration, not as the citation carrying the outcome. *)
  check ~msg:"2008-03-31 Easter+8: Annunciation's named sedes propria (RG96 Attamen a) claims the day first"
    2008 3 31
    "2008-03-31 monday season=paschaltide week=2 slug=annunciation-of-the-blessed-virgin-mary rank=class-1 \
     colour=white comms=[] in=annunciation-of-the-blessed-virgin-mary out=[]";
  (* Joseph's own general RG96 walk, finding 31 March already claimed
     (occupant reports Class1 there, still blocking per [is_blocking]),
     continues one more day to 1 April -- RG 97-98's "in order": the second
     I-class candidate to reach an already-occupied target keeps searching
     rather than displacing the first. *)
  check ~msg:"2008-04-01: Joseph's RG96 walk continues past the now-claimed 31 March (RG97-98 'in order')" 2008
    4 1
    "2008-04-01 tuesday season=paschaltide week=2 slug=joseph-spouse-of-the-bl-virgin-mary rank=class-1 \
     colour=white comms=[] in=joseph-spouse-of-the-bl-virgin-mary out=[]"

(* ------------------------------------------------------------------ *)
(* RG 96 Attamen (a) is CONDITIONAL ("quando est transferendum post
   Pascha") -- pinning both sides so the condition itself, not merely the
   exception's existence, is under test. All six weekdays independently
   confirmed via `date -d`. *)
(* ------------------------------------------------------------------ *)

(* Before Easter: 2057 (Easter 22 Apr), 2007 and 2012 (both Easter 8 Apr).
   In each, 25 March is a Sunday impeding the Annunciation (Lent III in
   2057; Passion Sunday, Dominica I Passionis, in 2007/2012), and the
   GENERAL RG96 walk lands on 26 March -- an ordinary III-class feria, band
   22/25, well before Easter -- so the condition never fires: no named
   exception, just the plain walk. Each arrival day's own displaced feria is
   RG25/RG109(e)-privileged (an ordinary Lent/Passiontide feria, impeded,
   must be commemorated) -- a second, independent confirmation of the
   RG24/25/RG109(e) mandate this file also pins directly below at 1900/1902,
   in a different code path (an ARRIVING transferred feast's displaced
   office, not a plain sanctoral winner's). *)
let test_annunciation_exception_not_triggered_general_walk_suffices () =
  check ~msg:"2057-03-26: general RG96 walk suffices (target before Easter, 22 Apr) -- no Attamen(a) exception"
    2057 3 26
    "2057-03-26 monday season=lent week=3 slug=annunciation-of-the-blessed-virgin-mary rank=class-1 \
     colour=white comms=[ef-lent-3-monday:privileged] in=annunciation-of-the-blessed-virgin-mary out=[]";
  check ~msg:"2007-03-26: general RG96 walk suffices (target before Easter, 8 Apr) -- no Attamen(a) exception"
    2007 3 26
    "2007-03-26 monday season=passiontide week=1 slug=annunciation-of-the-blessed-virgin-mary rank=class-1 \
     colour=white comms=[ef-passiontide-1-monday:privileged] in=annunciation-of-the-blessed-virgin-mary out=[]";
  check ~msg:"2012-03-26: general RG96 walk suffices (target before Easter, 8 Apr) -- no Attamen(a) exception"
    2012 3 26
    "2012-03-26 monday season=passiontide week=1 slug=annunciation-of-the-blessed-virgin-mary rank=class-1 \
     colour=white comms=[ef-passiontide-1-monday:privileged] in=annunciation-of-the-blessed-virgin-mary out=[]"

(* After Easter: 2016 (already pinned above, Easter+8 = 4 April) and 2024
   (Easter 31 March, Easter+8 = 8 April). In both, the general walk would
   cross Easter, so Attamen(a) fires and lands the feast on the Monday after
   Low Sunday exactly. Both arrival days are Paschaltide-2 (Class4
   ferias) -- RG26 (IV-class ferias never commemorated), so unlike the
   "before" trio above, no commemoration is left behind; a second,
   independent confirmation of RG26 in yet another code path. *)
let test_annunciation_exception_triggered_when_walk_would_cross_easter () =
  check
    ~msg:
      "2024-04-08: Easter+8 (Easter=31 Mar): RG96 Attamen(a) fires, arrival day is Class4 so no commemoration \
       (RG26)"
    2024 4 8
    "2024-04-08 monday season=paschaltide week=2 slug=annunciation-of-the-blessed-virgin-mary rank=class-1 \
     colour=white comms=[] in=annunciation-of-the-blessed-virgin-mary out=[]"
(* 2016's own pin (test_annunciation_transfer_inside_holy_week_2016) is the
   other half of this pair -- not repeated here to avoid asserting the same
   date twice. *)

(* ------------------------------------------------------------------ *)
(* 2011-07-04, the Precious Blood (register §4/§6, differential C10).
   Sacred Heart (Easter + 68, RG 91 entry 3) coincides with the fixed 1 July
   feast of the Most Precious Blood (entry 11) in 2011 (Easter = 24 April,
   so Easter + 68 = 1 July). Entry 3 outranks entry 11 outright (RG 97-98:
   the higher in the table is kept) -- no tie, unlike the 2008 case above.
   The general RG96 walk from 2 July must skip Visitation (2 July, II
   class, entry 19) and the ordinary Sunday (3 July, entry 15, II class)
   before landing on 4 July, an ordinary Class4 feria. All four weekdays
   independently confirmed via `date -d`. *)
let test_precious_blood_transfer_2011 () =
  check ~msg:"2011-07-01: Sacred Heart (RG91 entry 3) outranks the fixed Precious Blood (entry 11) outright"
    2011 7 1
    "2011-07-01 friday season=time-after-pentecost week=2 slug=ef-sacred-heart rank=class-1 colour=white \
     comms=[] in=- out=[precious-blood-of-our-lord-jesus-christ->2011-07-04]";
  check ~msg:"2011-07-02: the RG96 walk's first blocked day (Visitation, II class) -- Precious Blood not here"
    2011 7 2
    "2011-07-02 saturday season=time-after-pentecost week=2 slug=visitation-of-the-blessed-virgin-mary \
     rank=class-2 colour=white comms=[processus-and-martinian:ordinary] in=- out=[]";
  check ~msg:"2011-07-03: the RG96 walk's second blocked day (an ordinary Sunday, II class) -- still not here"
    2011 7 3
    "2011-07-03 sunday season=time-after-pentecost week=3 slug=ef-time-after-pentecost-sunday-3 rank=class-2 \
     colour=green comms=[] in=- out=[]";
  check ~msg:"2011-07-04: the first non-I/II-class day (RG96) -- the Precious Blood lands here" 2011 7 4
    "2011-07-04 monday season=time-after-pentecost week=3 slug=precious-blood-of-our-lord-jesus-christ \
     rank=class-1 colour=red comms=[] in=precious-blood-of-our-lord-jesus-christ out=[]"

(* ------------------------------------------------------------------ *)
(* All Souls falling on a Sunday (register §4, RG96 Attamen (b), primary-
   source-verified: "quando occurrit cum dominica, transfertur ... in feriam
   II sequentem"). 2025: All Souls (2 Nov) falls on an ordinary Sunday.
   Weekdays independently confirmed via `date -d`. *)
let test_all_souls_on_a_sunday_2025 () =
  (* RG91 entry 8's own parenthetical ("yields to an occurring Sunday") plus
     Attamen (b): the Sunday is simply observed, and RG94 ("a fixed-day
     commemoration is not carried with a transferred feast") means the
     transferred All Souls leaves nothing behind on the Sunday itself. *)
  check ~msg:"2025-11-02: All Souls yields to the occurring Sunday (RG91 entry 8), no commemoration (RG94)" 2025
    11 2
    "2025-11-02 sunday season=time-after-pentecost week=21 slug=ef-time-after-pentecost-sunday-21 rank=class-2 \
     colour=green comms=[] in=- out=[commemoration-of-all-souls->2025-11-03]";
  check ~msg:"2025-11-03: All Souls transfers to the following Monday, its sedes propria (RG96 Attamen b)" 2025
    11 3
    "2025-11-03 monday season=time-after-pentecost week=21 slug=commemoration-of-all-souls rank=class-1 \
     colour=black comms=[] in=commemoration-of-all-souls out=[]"

(* ------------------------------------------------------------------ *)
(* Christmas falling on a Sunday (RG91 entry 1: Nativity, Easter, Pentecost
   are I class WITH THEIR OWN OCTAVE, listed first in the whole table --
   temporal_ef.ml assigns 25 December the Nativity office unconditionally,
   so unlike a Feast of the Lord merely REPLACING an occurring Sunday (RG
   16(a), register §6), there is no Sunday-of-Advent/-per-annum candidate to
   even contest here: 25 December is never, in the EF temporal cycle, an
   "ordinary Sunday" in the first place. 2022: `date -d 2022-12-25 +%A` =
   Sunday, independently confirmed. *)
let test_christmas_on_a_sunday_2022 () =
  check ~msg:"2022-12-25 falling on a Sunday: the Nativity (RG91 entry 1) takes the day outright, no contest"
    2022 12 25
    "2022-12-25 sunday season=christmastide week=- slug=ef-nativity rank=class-1 colour=white comms=[] in=- \
     out=[]"

(* ------------------------------------------------------------------ *)
(* Holy Thursday is white (register §3b, RG 128(b) + RG 122, Task 16) while
   the surrounding Passiontide days stay violet -- the case the brief flags
   because colitur and lectio previously AGREED on violet (both wrong), so
   the lectio differential was structurally incapable of ever catching this;
   only a golden pin (or the missalemeum oracle, layer 4) can. 2026: Easter
   5 April (trusted via the property sweep). Weekdays independently
   confirmed via `date -d`. *)
let test_holy_thursday_is_white_2026 () =
  check ~msg:"2026-04-01 (Wednesday of Holy Week): ordinary Passiontide violet (RG128)" 2026 4 1
    "2026-04-01 wednesday season=passiontide week=2 slug=ef-passiontide-2-wednesday rank=class-1 colour=violet \
     comms=[] in=- out=[]";
  check
    ~msg:
      "2026-04-02 Holy Thursday: white (RG128(b)'s named exception + RG122's affirmative statement), not \
       Passiontide's violet"
    2026 4 2
    "2026-04-02 thursday season=passiontide week=2 slug=ef-passiontide-2-thursday rank=class-1 colour=white \
     comms=[] in=- out=[]";
  check ~msg:"2026-04-03 Good Friday: back to violet (RG128) -- Thursday's white is a one-day exception" 2026 4
    3
    "2026-04-03 friday season=passiontide week=2 slug=ef-passiontide-2-friday rank=class-1 colour=violet \
     comms=[] in=- out=[]"

(* ------------------------------------------------------------------ *)
(* Advent/Lent Ember ferias are commemorated when impeded (RG 24: "si vero
   impediuntur, commemorari debent" -- MUST be commemorated) while IV-class
   ferias never are (RG 26: "quae nunquam commemorantur") -- the fix-round-1
   F1/F2 finding, a Critical bug caught late precisely because no golden pin
   existed for it before now. Weekdays independently confirmed via
   `date -d`. *)
(* ------------------------------------------------------------------ *)

let test_ember_ferias_commemorated_when_impeded () =
  (* 1900-12-21: Advent Ember Friday (RG91 entry 18, II class) impeded by St
     Thomas (II class, universal, entry 16 -- Thomas outranks an II-class
     feria only because entry 16 < 18 in the table). RG24 makes the Ember
     feria's commemoration MANDATORY, and RG109(e) (corrected, fix round 1)
     makes it PRIVILEGED, not merely eligible. *)
  check ~msg:"1900-12-21: Advent Ember Friday, impeded, MUST be commemorated (RG24) and is privileged (RG109e)"
    1900 12 21
    "1900-12-21 friday season=advent week=3 slug=thomas rank=class-2 colour=red \
     comms=[ef-advent-ember-fri:privileged] in=- out=[]";
  (* 1902-02-22: Lent Ember Saturday (RG91 entry 18, II class) impeded by
     the Chair of St Peter (II class, universal, entry 16). Same RG24/
     RG109(e) mandate. *)
  check ~msg:"1902-02-22: Lent Ember Saturday, impeded, MUST be commemorated (RG24) and is privileged (RG109e)"
    1902 2 22
    "1902-02-22 saturday season=lent week=1 slug=chair-of-st-peter rank=class-2 colour=white \
     comms=[ef-lent-ember-sat:privileged] in=- out=[]"

let test_iv_class_ferias_never_commemorated () =
  (* 2026-07-22: an ordinary Time-after-Pentecost feria (Class4, RG91 entry
     28) impeded by St Mary Magdalene (III class). RG26 ("IV-class ferias
     are NEVER commemorated") means the displaced feria is dropped outright
     -- present in [omitted], never in [commemorations]. Asserting only
     "comms=[]" would be vacuous if there had been no losing candidate at
     all (one of this project's own catalogued vacuity flavours); the
     [omitted_has] check below proves a real candidate existed and was
     actively excluded, not merely absent. *)
  let d1 = fetch 2026 7 22 in
  Alcotest.(check bool) "2026-07-22: the displaced IV-class feria is in [omitted], proving RG26 actually fired"
    true
    (omitted_has d1 "ef-time-after-pentecost-8-wednesday");
  Alcotest.(check string) "2026-07-22: Mary Magdalene observed, no commemoration (RG26)"
    "2026-07-22 wednesday season=time-after-pentecost week=8 slug=mary-magdalene rank=class-3 colour=white \
     comms=[] in=- out=[]"
    (describe d1);
  let d2 = fetch 2026 8 10 in
  Alcotest.(check bool) "2026-08-10: the displaced IV-class feria is in [omitted], proving RG26 actually fired"
    true
    (omitted_has d2 "ef-time-after-pentecost-11-monday");
  Alcotest.(check string) "2026-08-10: St Lawrence observed, no commemoration (RG26)"
    "2026-08-10 monday season=time-after-pentecost week=11 slug=lawrence rank=class-2 colour=red comms=[] in=- \
     out=[]"
    (describe d2)

(* ------------------------------------------------------------------ *)
(* RG 111(b): a II-class SUNDAY admits only a commemoration "de festo II
   classis" -- a rank restriction, not "the best available ordinary
   candidate". 9 August falling on a Sunday: `romanus` (Class3,
   commemoration-only, register §6 notes his very existence is
   questionable, but that is irrelevant here -- RG111(b) excludes him on
   RANK alone, regardless of that open question) has no standing for the
   day's single slot. The brief names four recurring years (2009, 2015,
   2020, 2026); two are pinned here (2009 for an older-era instance, 2026
   for a current one) -- 2015/2020 were hand-checked via the CLI and found
   identical in shape (same slug family, same `romanus` exclusion, only the
   week number differs), so pinning all four would repeat the same
   assertion four times without exercising a different code path; rejected
   as duplicative. *)
let test_ii_class_sunday_admits_only_ii_class_commemoration () =
  let d2009 = fetch 2009 8 9 in
  Alcotest.(check bool) "2009-08-09: romanus (Class3) is offered and excluded, proving RG111(b) actually fired"
    true
    (omitted_has d2009 "romanus");
  Alcotest.(check string) "2009-08-09: the Sunday observed, no commemoration at all (RG111(b) rank floor)"
    "2009-08-09 sunday season=time-after-pentecost week=10 slug=ef-time-after-pentecost-sunday-10 rank=class-2 \
     colour=green comms=[] in=- out=[]"
    (describe d2009);
  let d2026 = fetch 2026 8 9 in
  Alcotest.(check bool) "2026-08-09: romanus (Class3) is offered and excluded, proving RG111(b) actually fired"
    true
    (omitted_has d2026 "romanus");
  Alcotest.(check string) "2026-08-09: the Sunday observed, no commemoration at all (RG111(b) rank floor)"
    "2026-08-09 sunday season=time-after-pentecost week=11 slug=ef-time-after-pentecost-sunday-11 rank=class-2 \
     colour=green comms=[] in=- out=[]"
    (describe d2026)

(* ------------------------------------------------------------------ *)
(* RG 16(a) (register §6.0, Caput III "De Dominicis", primary text quoted in
   this task's own report): "festum Domini I aut II classis, in dominica II
   classis occurrens, ... de dominica, proinde, nulla fit commemoratio" -- a
   Feast of the Lord, I or II class, impeding a II-class Sunday, takes the
   Sunday's own place with no commemoration of the Sunday at all, unlike
   every OTHER impeded II-class Sunday (RG 109(a)/RG 111(b), the
   [test_ii_class_sunday_admits_only_ii_class_commemoration] pin above).
   Two real dates, both directions, exactly the pair the task brief asks
   for. *)
(* ------------------------------------------------------------------ *)

(* 2028-08-06: the Transfiguration (6 Aug, II class, calendarium "IN
   TRANSFIGURATIONE D. N. I. C.") falls on an ordinary Time-after-Pentecost
   Sunday. `date -d 2028-08-06 +%A` = Sunday, independently confirmed. Also
   the exact date register §6.0's own reproduction names as a live instance
   of the bug this pin closes -- before this fix `colitur day` admitted
   "+ef-time-after-pentecost-sunday-9" here.

   CORRECTED, fix round 1 (IMPORTANT finding, item 2): this pin used to
   expect Pope Sixtus II et al. (6 August's own unrelated Class3 saint,
   Commemoration_only) admitted as an ordinary commemoration in the freed
   slot -- promoted from `colitur day`'s own actual output without
   consulting either the primary text or the oracle first (the exact
   vacuous-pin flavour the review caught, and this file's own header warns
   against). Re-derived properly this time:
   - PRIMARY TEXT: RG 16(a) itself says the winning Feast of the Lord holds
     the Sunday's place cum omnibus iuribus et privilegiis -- WITH ALL the
     Sunday's own rights and privileges. RG 111(b) is one of those: in
     dominicis II classis, una tantum admittitur commemoratio, SCILICET DE
     FESTO II CLASSIS -- a Sunday's own slot is reserved for a Class2
     candidate specifically. The day is still a dominica II classis for
     this purpose even though the Transfiguration, not the Sunday, is
     [observed] -- so Sixtus (Class3) has no standing for the slot at all,
     the same as on any other II-class Sunday (contrast
     [test_ii_class_sunday_admits_only_ii_class_commemoration] above,
     romanus, Class3, excluded the identical way on an ORDINARY II-class
     Sunday).
   - ORACLE, independently fetched (missalemeum's own /api/v5/calendar
     JSON, not the small-model webpage summary, which proved unreliable for
     this exact question): 2023-08-06 (a Sunday) -- title Transfiguration of
     Our Lord, commemorations empty, displaced Pope Sixtus II, Felicissimus
     and Agapitus, Martyrs -- Sixtus displaced, not commemorated. Control,
     2026-08-06 (a Thursday, no Sunday collision) -- Sixtus present in
     commemorations. Being a Sunday is exactly what excludes him.

   Deliberately NOT a bare "comms=[]" pin (this project's own catalogued
   vacuity flavour: a count/emptiness assertion that would pass even if
   nothing had ever been offered): [omitted_has] first proves the Sunday
   really WAS a candidate that reached [disposition] and was actively
   excluded, not merely never constructed. *)
let test_rg16a_lord_feast_no_sunday_commemoration_2028 () =
  let d = fetch 2028 8 6 in
  Alcotest.(check bool)
    "2028-08-06: the impeded Sunday is in [omitted], proving RG16(a) actively fired (not merely never offered)"
    true
    (omitted_has d "ef-time-after-pentecost-sunday-9");
  Alcotest.(check string)
    "2028-08-06: the Transfiguration observed; NO commemoration at all -- RG16(a)'s own \"cum omnibus iuribus \
     et privilegiis\" keeps the day a dominica II classis for RG111(b), so Sixtus (Class3) has no standing \
     either, oracle-confirmed"
    "2028-08-06 sunday season=time-after-pentecost week=9 slug=transfiguration-of-our-lord rank=class-2 \
     colour=white comms=[] in=- out=[]"
    (describe d)

(* 2025-02-02, the other real instance of the SAME pattern -- not a
   contrasting second direction, per this task's fix round 1 (CRITICAL
   finding, item 1, reverted; see register §6.0 for the full account).

   The Purification (2 Feb, calendarium "IN PURIFICATIONE B. MARIAE VIRG.")
   stays [subject = Lord] -- the user has ruled: follow the oracle.
   missalemeum treats it exactly as RG 16(a)'s own "festum Domini" case
   (independently fetched, `/api/v5/calendar` JSON): 2020-02-02 (a Sunday)
   -- `{"title":"Purification of the Blessed Virgin Mary","tags":["IV
   Sunday after Epiphany"],...,"commemorations":[],"displaced":[]}` -- the
   Sunday named only as a TAG (the underlying temporal placement), not
   commemorated at all; matches 2014-02-02 exactly. Contrast, the SAME
   oracle on an ordinary Marian feast (2019-09-08, the Nativity of the
   BVM): `{"title":"XIII Sunday after Pentecost",...,"commemorations":
   [{"title":"Nativity of the Blessed Virgin Mary",...}],...}` -- the
   Sunday observed, the feast merely commemorated, the OPPOSITE pattern --
   proving missalemeum does not treat every Marian feast this way, only the
   Purification specifically. `date -d 2025-02-02 +%A` = Sunday,
   independently confirmed.

   Unlike 2028-08-06, no second sanctoral candidate exists on 2 February
   (data/ef/sanctoral.sexp has exactly one 2 February entry) -- a genuinely
   clean "comms=[]" case, complementing the pair above rather than
   duplicating it. *)
let test_purification_on_a_sunday_2025 () =
  check
    ~msg:
      "2025-02-02: the Purification observed (subject Lord, unretagged -- the oracle's own treatment); NO \
       commemoration of the Sunday, oracle-confirmed"
    2025 2 2
    "2025-02-02 sunday season=time-after-epiphany week=4 slug=purification-of-the-blessed-virgin-mary \
     rank=class-2 colour=white comms=[] in=- out=[]"

let suite =
  ( "golden pins (known-tricky years)",
    [ Alcotest.test_case "Easter extreme: 1598 earliest (22 Mar, Gauss-verified)" `Quick
        test_easter_extreme_1598;
      Alcotest.test_case "Easter extreme: 1666 latest (25 Apr, Gauss-verified)" `Quick
        test_easter_extreme_1666;
      Alcotest.test_case "Easter extreme: 2038 late-modern instance of the latest date" `Quick
        test_easter_extreme_2038_late_modern;
      Alcotest.test_case "Annunciation transfer: 25 March falls inside Holy Week (2016)" `Quick
        test_annunciation_transfer_inside_holy_week_2016;
      Alcotest.test_case "Annunciation/Joseph double transfer (2008)" `Quick
        test_annunciation_joseph_double_transfer_2008;
      Alcotest.test_case "Annunciation RG96 exception NOT triggered: general walk suffices (2057, 2007, 2012)"
        `Quick test_annunciation_exception_not_triggered_general_walk_suffices;
      Alcotest.test_case "Annunciation RG96 exception triggered: walk would cross Easter (2024; see also 2016)"
        `Quick test_annunciation_exception_triggered_when_walk_would_cross_easter;
      Alcotest.test_case "2011-07-04: the Precious Blood transfer" `Quick test_precious_blood_transfer_2011;
      Alcotest.test_case "All Souls falling on a Sunday (2025)" `Quick test_all_souls_on_a_sunday_2025;
      Alcotest.test_case "Christmas falling on a Sunday (2022)" `Quick test_christmas_on_a_sunday_2022;
      Alcotest.test_case "Holy Thursday is white amid violet Passiontide (2026)" `Quick
        test_holy_thursday_is_white_2026;
      Alcotest.test_case "Advent/Lent Ember ferias commemorated when impeded (1900, 1902)" `Quick
        test_ember_ferias_commemorated_when_impeded;
      Alcotest.test_case "IV-class ferias never commemorated (2026)" `Quick test_iv_class_ferias_never_commemorated;
      Alcotest.test_case "RG111(b): a II-class Sunday admits only a de-festo-II-classis commemoration (2009, 2026)"
        `Quick test_ii_class_sunday_admits_only_ii_class_commemoration;
      Alcotest.test_case
        "RG16(a): a Feast of the Lord leaves the impeded Sunday with NO commemoration at all, not even an \
         unrelated saint's own (2028-08-06, rubric + oracle)"
        `Quick test_rg16a_lord_feast_no_sunday_commemoration_2028;
      Alcotest.test_case
        "RG16(a), the Purification (oracle-ruled): observed outright, the Sunday not commemorated (2025-02-02)"
        `Quick test_purification_on_a_sunday_2025
    ] )