[1791] added a database iterator test that would uncover an (unrelated) bug.

it checks the case for RRsets with the TTL of the first RR is later than that
of the second.  The original implementation has a bug in this case, but the
previous test was insufficient and fail to discover it.

src/lib/datasrc/tests/database_unittest.cc

@@ -501,80 +501,46 @@ private:
             }
 
             // Return faked data for tests
-            switch (step++) {
-                case 0:
-                    data[DatabaseAccessor::NAME_COLUMN] = "example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "A";
-                    data[DatabaseAccessor::TTL_COLUMN] = "3600";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "192.0.2.1";
-                    return (true);
-                case 1:
-                    data[DatabaseAccessor::NAME_COLUMN] = "example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "SOA";
-                    data[DatabaseAccessor::TTL_COLUMN] = "3600";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "ns1.example.org. admin.example.org. "
-                        "1234 3600 1800 2419200 7200";
-                    return (true);
-                case 2:
-                    data[DatabaseAccessor::NAME_COLUMN] = "x.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "A";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "192.0.2.1";
-                    return (true);
-                case 3:
-                    data[DatabaseAccessor::NAME_COLUMN] = "x.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "A";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "192.0.2.2";
-                    return (true);
-                case 4:
-                    data[DatabaseAccessor::NAME_COLUMN] = "x.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "AAAA";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "2001:db8::1";
-                    return (true);
-                case 5:
-                    data[DatabaseAccessor::NAME_COLUMN] = "x.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "AAAA";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "2001:db8::2";
-                    return (true);
-                case 6:
-                    data[DatabaseAccessor::NAME_COLUMN] = "x.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "RRSIG";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] =
-                        "A 5 3 3600 20000101000000 20000201000000 12345 "
-                        "example.org. FAKEFAKEFAKE";
-                    return (true);
-                case 7:
-                    // RRSIG for the same owner name but for a different type
-                    // to cover.  These two should be distinguished.
-                    data[DatabaseAccessor::NAME_COLUMN] = "x.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "RRSIG";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] =
-                        "AAAA 5 3 3600 20000101000000 20000201000000 12345 "
-                        "example.org. FAKEFAKEFAKEFAKE";
-                    return (true);
-                case 8:
-                    data[DatabaseAccessor::NAME_COLUMN] = "ttldiff.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "A";
-                    data[DatabaseAccessor::TTL_COLUMN] = "300";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "192.0.2.1";
-                    return (true);
-                case 9:
-                    data[DatabaseAccessor::NAME_COLUMN] = "ttldiff.example.org";
-                    data[DatabaseAccessor::TYPE_COLUMN] = "A";
-                    data[DatabaseAccessor::TTL_COLUMN] = "600";
-                    data[DatabaseAccessor::RDATA_COLUMN] = "192.0.2.2";
-                    return (true);
-                default:
-                    ADD_FAILURE() <<
-                        "Request past the end of iterator context";
-                case 10:
-                    return (false);
+            // This is the sequence of zone data in the order of appearance
+            // in the returned sequence from this iterator.
+            typedef const char* ColumnText[4];
+            const ColumnText zone_data[] = {
+                // A couple of basic RRs at the zone origin.
+                {"example.org", "A", "3600", "192.0.2.1"},
+                {"example.org", "SOA", "3600", "ns1.example.org. "
+                 "admin.example.org. 1234 3600 1800 2419200 7200"},
+                // RRsets sharing the same owner name with multiple RRs.
+                {"x.example.org", "A", "300", "192.0.2.1"},
+                {"x.example.org", "A", "300", "192.0.2.2"},
+                {"x.example.org", "AAAA", "300", "2001:db8::1"},
+                {"x.example.org", "AAAA", "300", "2001:db8::2"},
+                // RRSIGs.  Covered types are different and these two should
+                // be distinguished.
+                {"x.example.org", "RRSIG", "300",
+                 "A 5 3 3600 20000101000000 20000201000000 12345 "
+                 "example.org. FAKEFAKEFAKE"},
+                {"x.example.org", "RRSIG", "300",
+                 "AAAA 5 3 3600 20000101000000 20000201000000 12345 "
+                 "example.org. FAKEFAKEFAKEFAKE"},
+                // Mixture of different TTLs.  Covering both cases of small
+                // then large and large then small.  In either case the smaller
+                // TTL should win.
+                {"ttldiff.example.org", "A", "300", "192.0.2.1"},
+                {"ttldiff.example.org", "A", "600", "192.0.2.2"},
+                {"ttldiff2.example.org", "AAAA", "600", "2001:db8::1"},
+                {"ttldiff2.example.org", "AAAA", "300", "2001:db8::2"}};
+            const size_t num_rrs = sizeof(zone_data) / sizeof(zone_data[0]);
+            if (step > num_rrs) {
+                ADD_FAILURE() << "Request past the end of iterator context";
+            } else if (step < num_rrs) {
+                data[DatabaseAccessor::NAME_COLUMN] = zone_data[step][0];
+                data[DatabaseAccessor::TYPE_COLUMN] = zone_data[step][1];
+                data[DatabaseAccessor::TTL_COLUMN] = zone_data[step][2];
+                data[DatabaseAccessor::RDATA_COLUMN] = zone_data[step][3];
+                ++step;
+                return (true);
             }
+            return (false);
         }
     };
     class EmptyIteratorContext : public IteratorContext {
@@ -1431,6 +1397,14 @@ TYPED_TEST(DatabaseClientTest, iterator) {
     checkRRset(rrset, Name("ttldiff.example.org"), this->qclass_, RRType::A(),
                RRTTL(300), this->expected_rdatas_);
 
+    rrset = it->getNextRRset();
+    ASSERT_NE(ConstRRsetPtr(), rrset);
+    this->expected_rdatas_.clear();
+    this->expected_rdatas_.push_back("2001:db8::1");
+    this->expected_rdatas_.push_back("2001:db8::2");
+    checkRRset(rrset, Name("ttldiff2.example.org"), this->qclass_,
+               RRType::AAAA(), RRTTL(300), this->expected_rdatas_);
+
     EXPECT_EQ(ConstRRsetPtr(), it->getNextRRset());
 }