fix(citation): complete the modern tradition, and test the shipped file

Apocalypse -> Revelation was missing from [modern] while `revelation` was
already a declared tradition target, so the target existed with nothing
mapping onto it. Same Vulgate-to-modern shape as Ecclesiasticus -> Sirach.

The injectivity test used to hand-copy the mapping table, which asserted
things about the copy and nothing about the artifact: a mapping added to
traditions.ini and forgotten in the test would have passed. It now reads
lang/traditions.ini and additionally asserts that [vulgate] is empty --
an entry there would silently renumber the DEFAULT, the one thing this
design promises never happens -- and that no declared target is left
unreachable.

Mutation-proved three ways: declaring an unused target, deleting a
mapping, and adding an entry to [vulgate] each redden it, the first two
naming the offending book.

2 files changed, 41 insertions, 4 deletions

diff --git a/lang/traditions.ini b/lang/traditions.ini
index e2d53ab..46f6ee7 100644
--- a/lang/traditions.ini
+++ b/lang/traditions.ini
@@ -19,3 +19,4 @@ esdras_2       = nehemiah
 ecclesiasticus = sirach
 osee           = hosea
 jonas          = jonah
+apocalypse     = revelation
diff --git a/test/test_citation.ml b/test/test_citation.ml
index d9be86e..1efaa10 100644
--- a/test/test_citation.ml
+++ b/test/test_citation.ml
@@ -180,13 +180,49 @@ let test_every_data_file_token_resolves () =
    always a typo -- it would silently merge two books -- so this asserts the
    mapping is injective, not merely that every id is known. *)
 let test_modern_tradition_is_injective () =
-  let fields =
-    [ ("kings_3", "kings_1"); ("kings_4", "kings_2");
-      ("esdras_2", "nehemiah"); ("ecclesiasticus", "sirach");
-      ("osee", "hosea"); ("jonas", "jonah") ]
+  (* READ the shipped file. An earlier version of this test hand-copied the
+     table, which asserted things about the copy and nothing at all about the
+     artifact -- a mapping added to traditions.ini and forgotten here would
+     have passed. *)
+  let text =
+    let ic = open_in_bin "../lang/traditions.ini" in
+    let s = really_input_string ic (in_channel_length ic) in
+    close_in ic; s
   in
+  let sections =
+    match Colitur_kernel.Overlay_ini.parse_sections text with
+    | Ok ss -> ss
+    | Error e -> Alcotest.failf "lang/traditions.ini: %s" e
+  in
+  let section name =
+    List.filter_map
+      (fun (sc : Colitur_kernel.Overlay_ini.section) ->
+        if sc.Colitur_kernel.Overlay_ini.name = name then
+          Some sc.Colitur_kernel.Overlay_ini.fields
+        else None)
+      sections
+    |> List.concat
+  in
+  (* [vulgate] must be the identity: an entry there would silently renumber
+     the DEFAULT, which is the one thing this design promises never happens. *)
+  Alcotest.(check (list (pair string string))) "vulgate is identity" []
+    (section "vulgate");
+  let fields = section "modern" in
+  Alcotest.(check bool) "modern is not empty" true (fields <> []);
   Alcotest.(check (list string)) "all ids known" [] (B.unknown_fields fields);
+  (* every declared tradition target is actually reachable -- an unused target
+     is either a forgotten mapping or dead weight *)
   let targets = List.map snd fields in
+  (* [B.tokens] is (spelling, id) pairs, so membership of an ID is a lookup
+     over the VALUES, not [mem_assoc] over the keys. Getting that backwards
+     flags every ordinary book as an unused target. *)
+  let cited = List.map (fun (_, i) -> B.to_string i) B.tokens in
+  List.iter
+    (fun id ->
+      let n = B.to_string id in
+      if (not (List.mem n cited)) && not (List.mem n targets) then
+        Alcotest.failf "%s is a declared target no tradition maps onto" n)
+    B.all;
   let uniq = List.sort_uniq compare targets in
   Alcotest.(check int) "no two ids share a target"
     (List.length targets) (List.length uniq)