Noissue - Add tests for base domain extraction

test/domain.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 139 matching lines @@
 
       let expected = parts.slice(Math.max(0, i - offset), i).join(".");
       expected += (expected ? "." : "") + suffix;
 
       test.equal(getDomain(hostname), expected,
                  `getDomain("${hostname}") == "${expected}"` +
                  ` with {suffix: "${suffix}", offset: ${offset}}`);
     }
   }
 
-  // Test unknown suffixes.
+  // Unknown suffixes.
   test.equal(typeof publicSuffixes["localhost"], "undefined");
   test.equal(typeof publicSuffixes["localhost.localdomain"], "undefined");
 
   test.equal(getDomain("localhost"), "localhost");
   test.equal(getDomain("localhost.localdomain"), "localhost.localdomain");
   test.equal(getDomain("mail.localhost.localdomain"), "localhost.localdomain");
   test.equal(getDomain("www.example.localhost.localdomain"),
              "localhost.localdomain");
 
-  // Test unknown suffixes that overlap partly with known suffixes.
+  // Unknown suffixes that overlap partly with known suffixes.
   test.equal(typeof publicSuffixes["example.com"], "undefined");
   test.equal(typeof publicSuffixes["africa.com"], "number");
   test.equal(typeof publicSuffixes["compute.amazonaws.com"], "number");
 
   test.equal(getDomain("example.com"), "example.com");
   test.equal(getDomain("mail.example.com"), "example.com");
   test.equal(getDomain("secure.mail.example.com"), "example.com");
 
+  // Cascading offsets.
+
+  // If these sanity checks fail, look for other examles of cascading offsets
+  // from the public suffix list.
+  test.equal(
+    typeof publicSuffixes[
+      "images.example.s3.dualstack.us-east-1.amazonaws.com"
+    ],
+    "undefined"
+  );
+  test.equal(
+    typeof publicSuffixes["example.s3.dualstack.us-east-1.amazonaws.com"],
+    "undefined"
+  );
+  test.equal(publicSuffixes["s3.dualstack.us-east-1.amazonaws.com"], 1);
+  test.equal(typeof publicSuffixes["dualstack.us-east-1.amazonaws.com"],
+             "undefined");
+  test.equal(typeof publicSuffixes["example.us-east-1.amazonaws.com"],
+             "undefined");
+  test.equal(publicSuffixes["us-east-1.amazonaws.com"], 1);
+  test.equal(typeof publicSuffixes["example.amazonaws.com"], "undefined");
+  test.equal(typeof publicSuffixes["amazonaws.com"], "undefined");
+
+  test.equal(getDomain("images.example.s3.dualstack.us-east-1.amazonaws.com"),
+            "example.s3.dualstack.us-east-1.amazonaws.com");
+  test.equal(getDomain("example.s3.dualstack.us-east-1.amazonaws.com"),
+            "example.s3.dualstack.us-east-1.amazonaws.com");
+  test.equal(getDomain("s3.dualstack.us-east-1.amazonaws.com"),
+            "s3.dualstack.us-east-1.amazonaws.com");
+  test.equal(getDomain("dualstack.us-east-1.amazonaws.com"),
+            "dualstack.us-east-1.amazonaws.com");
+  test.equal(getDomain("example.us-east-1.amazonaws.com"),
+            "example.us-east-1.amazonaws.com");
+  test.equal(getDomain("us-east-1.amazonaws.com"), "us-east-1.amazonaws.com");
+  test.equal(getDomain("example.amazonaws.com"), "amazonaws.com");
+  test.equal(getDomain("amazonaws.com"), "amazonaws.com");
+
+  // Edge case.
   test.equal(getDomain(""), "");
 
   test.done();
 };