1 files changed, 34 insertions, 0 deletions
diff --git a/internal/calendar/temporal_ef_test.go b/internal/calendar/temporal_ef_test.go
index 1290a59..e8ef391 100644
--- a/internal/calendar/temporal_ef_test.go
+++ b/internal/calendar/temporal_ef_test.go
@@ -300,3 +300,37 @@ func TestTemporalEFBVMSaturday(t *testing.T) {
 		}
 	}
 }
+
+// TestTemporalEFRogationDays pins RG 87's Minor Litanies: "Litaniae minores seu
+// Rogationes, per se, assignantur feriis II, III et IV ante festum Ascensionis
+// Domini." Easter+36 and +37 are that Monday and Tuesday; RG 128(d) makes them
+// violet, "for the procession and Mass of the Greater and Lesser Litanies" --
+// a penitential note inside white Paschaltide.
+//
+// The Wednesday is asserted in the opposite direction on purpose. Easter+38 is
+// by construction the Vigil of the Ascension, II class, which wins the day; the
+// rubric asks for a COMMEMORATION there, which this function cannot express
+// since it returns one office per day. A change that extended the Rogation
+// branch to +38 to "complete" the rubric would silently displace the Vigil, and
+// this test is what stops it.
+func TestTemporalEFRogationDays(t *testing.T) {
+	// 2027: Easter is 28 March, so the Rogation days are 3-5 May and the
+	// Monday is unimpeded that year.
+	easter := d("2027-03-28")
+	for off, want := range map[int]string{36: "ef-rogation-monday", 37: "ef-rogation-tuesday"} {
+		day := easter.AddDate(0, 0, off)
+		got := temporalEF(day)
+		if got.Cel.Slug != want {
+			t.Errorf("Easter+%d (%s): slug = %q, want %q", off, day.Format("2006-01-02"), got.Cel.Slug, want)
+		}
+		if got.Cel.Colour != Violet {
+			t.Errorf("Easter+%d (%s): colour = %s, want violet (RG 128(d))",
+				off, day.Format("2006-01-02"), got.Cel.Colour)
+		}
+	}
+	// Easter+38 is the Ascension's Vigil and must stay so.
+	if got := temporalEF(easter.AddDate(0, 0, 38)); got.Cel.Slug != "ef-ascension-vigil" {
+		t.Errorf("Easter+38: slug = %q, want ef-ascension-vigil -- the Rogation Wednesday's "+
+			"commemoration cannot be built here without displacing the Vigil", got.Cel.Slug)
+	}
+}