[1140] comparison test added in rdata_txt_like_unittest.cc

src/lib/dns/rdata/generic/detail/txt_like.h

@@ -188,15 +188,18 @@ public:
         // This implementation is not efficient.  Revisit this (TBD).
         OutputBuffer this_buffer(0);
         toWire(this_buffer);
+        uint8_t const* const this_data = (uint8_t const*)this_buffer.getData();
         size_t this_len = this_buffer.getLength();
 
         OutputBuffer other_buffer(0);
         other.toWire(other_buffer);
+        uint8_t const* const other_data
+                                      = (uint8_t const*)other_buffer.getData();
         const size_t other_len = other_buffer.getLength();
 
         const size_t cmplen = min(this_len, other_len);
-        const int cmp = memcmp(this_buffer.getData(), other_buffer.getData(),
-                               cmplen);
+        const int cmp = memcmp(this_data, other_data, cmplen);
+
         if (cmp != 0) {
             return (cmp);
         } else {

src/lib/dns/tests/rdata_txt_like_unittest.cc

@@ -215,4 +215,39 @@ TYPED_TEST(Rdata_TXT_LIKE_Test, assignment) {
     EXPECT_EQ(0, rdata2.compare(rdata1));
 }
 
+TYPED_TEST(Rdata_TXT_LIKE_Test, compare) {
+    string const txt1 ("aaaaaaaa");
+    string const txt2 ("aaaaaaaaaa");
+    string const txt3 ("bbbbbbbb");
+    string const txt4 (129, 'a');
+    string const txt5 (128, 'b');
+
+    EXPECT_EQ(TypeParam(txt1).compare(TypeParam(txt1)), 0);
+
+    EXPECT_LT(TypeParam("").compare(TypeParam(txt1)), 0);
+    EXPECT_GT(TypeParam(txt1).compare(TypeParam("")), 0);
+
+    EXPECT_LT(TypeParam(txt1).compare(TypeParam(txt2)), 0);
+    EXPECT_GT(TypeParam(txt2).compare(TypeParam(txt1)), 0);
+
+    EXPECT_LT(TypeParam(txt1).compare(TypeParam(txt3)), 0);
+    EXPECT_GT(TypeParam(txt3).compare(TypeParam(txt1)), 0);
+
+    // we're comparing the data raw, starting at the length octet, so a shorter
+    // string sorts before a longer one no matter the lexicopraphical order
+    EXPECT_LT(TypeParam(txt3).compare(TypeParam(txt2)), 0);
+    EXPECT_GT(TypeParam(txt2).compare(TypeParam(txt3)), 0);
+
+    // to make sure the length octet compares unsigned
+    EXPECT_LT(TypeParam(txt1).compare(TypeParam(txt4)), 0);
+    EXPECT_GT(TypeParam(txt4).compare(TypeParam(txt1)), 0);
+
+    EXPECT_LT(TypeParam(txt5).compare(TypeParam(txt4)), 0);
+    EXPECT_GT(TypeParam(txt4).compare(TypeParam(txt5)), 0);
+
+    // comparison attempt between incompatible RR types should be rejected
+    EXPECT_THROW(TypeParam(txt1).compare(*this->rdata_nomatch),
+                 bad_cast);
+}
+
 }