Measure how often DNS hostnames aren't in preferred name form.

net/dns/dns_util_unittest.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/dns/dns_util.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace net {
 
@@ skipping 51 matching lines @@
             DNSDomainToString(IncludeNUL("\003foo\003bar\002uk")));
 
   // It should cope with a lack of root label.
   EXPECT_EQ("foo.bar", DNSDomainToString("\003foo\003bar"));
 
   // Invalid inputs should return an empty string.
   EXPECT_EQ("", DNSDomainToString(IncludeNUL("\x80")));
   EXPECT_EQ("", DNSDomainToString("\x06"));
 }
 
+TEST_F(DNSUtilTest, IsValidDNSDomain) {
+  const char* const bad_hostnames[] = {
+      "%20%20noodles.blorg", "noo dles.blorg ",    "noo dles.blorg. ",
+      "^noodles.blorg",      "noodles^.blorg",     "noo&dles.blorg",
+      "noodles.blorg`",      "www.-noodles.blorg",
+  };
+
+  for (size_t i = 0; i < arraysize(bad_hostnames); ++i) {
+    EXPECT_FALSE(IsValidDNSDomain(bad_hostnames[i]));
+  }
+
+  const char* const good_hostnames[] = {
+      "www.noodles.blorg",   "1www.noodles.blorg", "www.2noodles.blorg",
+      "www.n--oodles.blorg", "www.noodl_es.blorg", "www.no-_odles.blorg",
+      "www_.noodles.blorg",  "www.noodles.blorg.", "_privet._tcp.local",
+  };
+
+  for (size_t i = 0; i < arraysize(good_hostnames); ++i) {
+    EXPECT_TRUE(IsValidDNSDomain(good_hostnames[i]));
+  }
+}
+
 }  // namespace net