1 files changed, 45 insertions, 0 deletions
diff --git a/internal/calendar/precedence_ef_repro_test.go b/internal/calendar/precedence_ef_repro_test.go
new file mode 100644
index 0000000..6c333d0
--- /dev/null
+++ b/internal/calendar/precedence_ef_repro_test.go
@@ -0,0 +1,45 @@
+package calendar_test
+
+// Reproduction tests for three named EF precedence defects (colitur's
+// differential/oracle audit against lectio's ~66-line EF precedence
+// approximation, internal/calendar/precedence_ef.go). Each test fails before
+// its fix and passes after -- see the report for the exact pre-fix failure
+// message. These exercise the REAL tridentine sanctoral data
+// (caldata.Tridentine()) through the public Compute entry point, since the
+// bugs are about how real fixed-date feasts interact with the temporal
+// calendar, not about precedenceEF's arithmetic in isolation (that is
+// covered separately, package-internal, in precedence_ef_test.go).
+
+import (
+	"testing"
+	"time"
+
+	"github.com/lukaszkasprzak/lectio/internal/caldata"
+	"github.com/lukaszkasprzak/lectio/internal/calendar"
+)
+
+func efCompute(date string) calendar.LiturgicalDay {
+	sel := calendar.DefaultSelection()
+	sel.Form = "old"
+	d, _ := time.Parse("2006-01-02", date)
+	return calendar.Compute(d.UTC(), sel, []calendar.Layer{caldata.Tridentine()})
+}
+
+// TestJosephYieldsToSundayOfLent: RG 91 entry 6 (Sundays of Lent, I class)
+// vs entry 11 (I-class feasts of the universal Church not above) -- the
+// Sunday holds; St Joseph (19 March) transfers to the next free day (RG 95,
+// RG 96), landing on the 20th. Before the fix (defect 4: Sunday ranks), Lent
+// Sundays were wrongly II class, so Joseph (I class) won outright every time
+// this collision occurred.
+func TestJosephYieldsToSundayOfLent(t *testing.T) {
+	for _, year := range []string{"2006", "2017", "2023", "2028", "2034", "2045"} {
+		sunday := efCompute(year + "-03-19")
+		if sunday.Observed.Slug == "joseph-spouse-of-the-bl-virgin-mary" {
+			t.Errorf("%s-03-19 observed = %q want the Lent Sunday (RG 91 entry 6 beats entry 11)", year, sunday.Observed.Slug)
+		}
+		next := efCompute(year + "-03-20")
+		if next.Observed.Slug != "joseph-spouse-of-the-bl-virgin-mary" {
+			t.Errorf("%s-03-20 observed = %q want joseph-spouse-of-the-bl-virgin-mary (transferred one day, RG 96)", year, next.Observed.Slug)
+		}
+	}
+}