2 files changed, 46 insertions, 1 deletions
diff --git a/test/test_colitur.ml b/test/test_colitur.ml
index 293e439..ae58607 100644
--- a/test/test_colitur.ml
+++ b/test/test_colitur.ml
@@ -2,4 +2,4 @@
 let () =
   Alcotest.run "colitur"
     [ Test_date.suite; Test_computus.suite; Test_colour.suite; Test_slug.suite; Test_names.suite;
-      Test_overlay.suite; Test_temporal_ef.suite ]
+      Test_overlay.suite; Test_temporal_ef.suite; Test_validate.suite ]
diff --git a/test/test_validate.ml b/test/test_validate.ml
new file mode 100644
index 0000000..e293dfd
--- /dev/null
+++ b/test/test_validate.ml
@@ -0,0 +1,45 @@
+module Val = Colitur_kernel.Validate
+module V = Rite_ef.Vocab_ef
+module T = Rite_ef.Temporal_ef
+
+let run year =
+  Val.run V.vocab ~year_start:T.year_start ~temporal:T.temporal ~year
+
+let check_year year =
+  match run year with
+  | [] -> ()
+  | fs ->
+      Alcotest.failf "%d: %s" year
+        (String.concat "; " (List.map Val.failure_to_string (List.filteri (fun i _ -> i < 5) fs)))
+
+let test_landmark_years () = List.iter check_year [ 1583; 2026; 2035; 9998 ]
+
+(* Easter extremes: the earliest possible date is 22 March and the latest is
+   25 April. Find one of each inside the domain and validate those years. *)
+let extreme_years () =
+  let module C = Colitur_kernel.Computus in
+  let module D = Colitur_kernel.Date in
+  let earliest = ref None and latest = ref None in
+  for y = 1583 to 2500 do
+    let e = C.gregorian_easter y in
+    if D.month e = 3 && D.day e = 22 && !earliest = None then earliest := Some y;
+    if D.month e = 4 && D.day e = 25 && !latest = None then latest := Some y
+  done;
+  List.filter_map Fun.id [ !earliest; !latest ]
+
+let test_easter_extremes () =
+  let ys = extreme_years () in
+  Alcotest.(check bool) "found at least one extreme year" true (ys <> []);
+  List.iter check_year ys
+
+(* The confidence-to-9999 core: random years across the whole domain. *)
+let prop_invariants =
+  QCheck.Test.make ~count:200 ~name:"EF temporal invariants hold across 1583..9998"
+    (QCheck.int_range 1583 9998)
+    (fun y -> run y = [])
+
+let suite =
+  ( "Validate",
+    [ Alcotest.test_case "landmark years" `Quick test_landmark_years;
+      Alcotest.test_case "easter extremes" `Quick test_easter_extremes ]
+    @ List.map QCheck_alcotest.to_alcotest [ prop_invariants ] )