diff --git a/util.d b/util.d
index 044e2c8..f829f1f 100644
--- a/util.d
+++ b/util.d
@@ -65,6 +65,12 @@ parseBook(in string book)
 	return book.tr("-_", "  ");
 }
 
+@safe unittest
+{
+	assert(parseBook("1-Corinthians") == "1 Corinthians");
+	assert(parseBook("1_Corinthians") == "1 Corinthians");
+}
+
 ushort
 terminalColumns() @trusted
 {