[2420] added tests with RRSIG-only RRsets.

Due to the extension to RdataSet::find(), the tested code doesn't have to
be modified.

src/lib/datasrc/tests/memory/zone_finder_unittest.cc

@@ -1358,6 +1358,74 @@ TEST_F(InMemoryZoneFinderTest, findNSEC3ForBadZone) {
                  DataSourceError);
 }
 
+TEST_F(InMemoryZoneFinderTest, findOrphanRRSIG) {
+    // Make the zone "NSEC signed"
+    addToZoneData(rr_nsec_);
+    const ZoneFinder::FindResultFlags expected_flags =
+        ZoneFinder::RESULT_NSEC_SIGNED;
+
+    // Add A for ns.example.org, and RRSIG-only covering TXT for the same name.
+    // query for the TXT should result in NXRRSET.
+    addToZoneData(rr_ns_a_);
+    updater_.add(ConstRRsetPtr(),
+                 textToRRset(
+                     "ns.example.org. 300 IN RRSIG TXT 5 3 300 20120814220826 "
+                     "20120715220826 1234 example.com. FAKE"));
+    findTest(Name("ns.example.org"), RRType::TXT(),
+             ZoneFinder::NXRRSET, true, ConstRRsetPtr(), expected_flags);
+
+    // Add RRSIG-only covering NSEC.  This shouldn't be returned when NSEC is
+    // requested, whether it's for NXRRSET or NXDOMAIN
+    updater_.add(ConstRRsetPtr(),
+                 textToRRset(
+                     "ns.example.org. 300 IN RRSIG NSEC 5 3 300 "
+                     "20120814220826 20120715220826 1234 example.com. FAKE"));
+    // The added RRSIG for NSEC could be used for NXRRSET but shouldn't
+    findTest(Name("ns.example.org"), RRType::TXT(),
+             ZoneFinder::NXRRSET, true, ConstRRsetPtr(),
+             expected_flags, NULL, ZoneFinder::FIND_DNSSEC);
+    // The added RRSIG for NSEC could be used for NXDOMAIN but shouldn't
+    findTest(Name("nz.example.org"), RRType::A(),
+             ZoneFinder::NXDOMAIN, true, rr_nsec_,
+             expected_flags, NULL, ZoneFinder::FIND_DNSSEC);
+
+    // RRSIG-only CNAME shouldn't be accidentally confused with real CNAME.
+    updater_.add(ConstRRsetPtr(),
+                 textToRRset(
+                     "nocname.example.org. 300 IN RRSIG CNAME 5 3 300 "
+                     "20120814220826 20120715220826 1234 example.com. FAKE"));
+    findTest(Name("nocname.example.org"), RRType::A(),
+             ZoneFinder::NXRRSET, true, ConstRRsetPtr(), expected_flags);
+
+    // RRSIG-only for NS wouldn't invoke delegation anyway, but we check this
+    // case explicitly.
+    updater_.add(ConstRRsetPtr(),
+                 textToRRset(
+                     "nodelegation.example.org. 300 IN RRSIG NS 5 3 300 "
+                     "20120814220826 20120715220826 1234 example.com. FAKE"));
+    findTest(Name("nodelegation.example.org"), RRType::A(),
+             ZoneFinder::NXRRSET, true, ConstRRsetPtr(), expected_flags);
+    findTest(Name("www.nodelegation.example.org"), RRType::A(),
+             ZoneFinder::NXDOMAIN, true, ConstRRsetPtr(), expected_flags);
+
+    // Same for RRSIG-only for DNAME
+    updater_.add(ConstRRsetPtr(),
+                 textToRRset(
+                     "nodname.example.org. 300 IN RRSIG DNAME 5 3 300 "
+                     "20120814220826 20120715220826 1234 example.com. FAKE"));
+    findTest(Name("www.nodname.example.org"), RRType::A(),
+             ZoneFinder::NXDOMAIN, true, ConstRRsetPtr(), expected_flags);
+    // If we have a delegation NS at this node, it will be a bit trickier,
+    // because the zonecut processing actually takes place at the node.
+    // But the RRSIG-only for DNAME shouldn't confuse the process and the NS
+    // should win.
+    ConstRRsetPtr ns_rrset =
+        textToRRset("nodname.example.org. 300 IN NS ns.nodname.example.org.");
+    addToZoneData(ns_rrset);
+    findTest(Name("www.nodname.example.org"), RRType::A(),
+             ZoneFinder::DELEGATION, true, ns_rrset);
+}
+
 /// \brief NSEC3 specific tests fixture for the InMemoryZoneFinder class
 class InMemoryZoneFinderNSEC3Test : public InMemoryZoneFinderTest {
 public: