diff --git a/tests/dns/rdata_test.c b/tests/dns/rdata_test.c
index f2e9ba62e6..ab6b2a974c 100644
--- a/tests/dns/rdata_test.c
+++ b/tests/dns/rdata_test.c
@@ -2420,8 +2420,7 @@ ISC_RUN_TEST_IMPL(nsec) {
  * RFC 5155.
  */
 ISC_RUN_TEST_IMPL(nsec3) {
-	text_ok_t text_ok[] = { TEXT_INVALID(""),
-				TEXT_INVALID("."),
+	text_ok_t text_ok[] = { TEXT_INVALID(""), TEXT_INVALID("."),
 				TEXT_INVALID(". RRSIG"),
 				TEXT_INVALID("1 0 10 76931F"),
 				TEXT_INVALID("1 0 10 76931F "
@@ -2437,9 +2436,38 @@ ISC_RUN_TEST_IMPL(nsec3) {
 					   "AJHVGTICN6K0VDA53GCHFMT219SRRQLM"),
 				TEXT_VALID("1 0 10 - "
 					   "AJHVGTICN6K0VDA53GCHFMT219SRRQLM"),
+				/* 123456789012345678901234567890123456789 */
+				TEXT_VALID("2 0 10 - "
+					   "64P36D1L6ORJGE9G64P36D1L6ORJGE9G64P"
+					   "36D1L6ORJGE9G64P36D1L6ORJGE8"),
+				/* 1234567890123456789012345678901234567890 */
+				TEXT_INVALID("2 0 10 - "
+					     "64P36D1L6ORJGE9G64P36D1L6ORJGE9G6"
+					     "4P36D1L6ORJGE9G64P36D1L6ORJGE9G"),
 				TEXT_SENTINEL() };
+	wire_ok_t wire_ok[] = {
+		WIRE_VALID(0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00),
+		/* maximal hash */
+		WIRE_VALID(0x00, 0x00, 0x00, 0x00, 0x00, 0x27, 0x01, 0x02, 0x03,
+			   0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x00, 0x01, 0x02,
+			   0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x00, 0x01,
+			   0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x00,
+			   0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+			   0x09),
+		/* Too big hash */
+		WIRE_INVALID(0x00, 0x00, 0x00, 0x00, 0x00, 0x28, 0x01, 0x02,
+			     0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x00,
+			     0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+			     0x09, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
+			     0x07, 0x08, 0x09, 0x00, 0x01, 0x02, 0x03, 0x04,
+			     0x05, 0x06, 0x07, 0x08, 0x09, 0x00),
+		/*
+		 * Sentinel.
+		 */
+		WIRE_SENTINEL()
+	};
 
-	check_rdata(text_ok, NULL, NULL, false, dns_rdataclass_in,
+	check_rdata(text_ok, wire_ok, NULL, false, dns_rdataclass_in,
 		    dns_rdatatype_nsec3, sizeof(dns_rdata_nsec3_t));
 }