AK: Add missing default port definitions for FTP scheme URLs

This is defined in the spec, but was missing in our table. Fix this, and
add a spec comment for what is missing. Also begin a basic text based
test for URL, so we can get some coverage of LibWeb's usage of URL too.

AK/URL.cpp

@@ -204,22 +204,29 @@ bool URL::compute_validity() const
     return true;
 }
 
+// https://url.spec.whatwg.org/#default-port
 u16 URL::default_port_for_scheme(StringView scheme)
 {
+    // Spec defined mappings with port:
+    if (scheme == "ftp")
+        return 21;
     if (scheme == "http")
         return 80;
     if (scheme == "https")
         return 443;
+    if (scheme == "ws")
+        return 80;
+    if (scheme == "wss")
+        return 443;
+
+    // NOTE: not in spec, but we support these too
     if (scheme == "gemini")
         return 1965;
     if (scheme == "irc")
         return 6667;
     if (scheme == "ircs")
         return 6697;
-    if (scheme == "ws")
+
-        return 80;
-    if (scheme == "wss")
-        return 443;
     return 0;
 }
 

Tests/LibWeb/Text/expected/URL/url.txt

@@ -0,0 +1,9 @@
+ftp://serenityos.org:21
+protocol => 'ftp:'
+username => ''
+password => ''
+host => 'serenityos.org'
+hostname => 'serenityos.org'
+port => ''
+pathname => '/'
+search => ''

Tests/LibWeb/Text/input/URL/url.html

@@ -0,0 +1,23 @@
+<script src="../include.js"></script>
+<script>
+    test(() => {
+        function printURL(input) {
+            println(input);
+            const url = new URL(input);
+            println(`protocol => '${url.protocol}'`);
+            println(`username => '${url.username}'`);
+            println(`password => '${url.password}'`);
+            println(`host => '${url.host}'`);
+            println(`hostname => '${url.hostname}'`);
+            println(`port => '${url.port}'`);
+            println(`pathname => '${url.pathname}'`);
+            println(`search => '${url.search}'`);
+        }
+
+        for (url of [
+            'ftp://serenityos.org:21',
+        ]) {
+            printURL(url);
+        }
+    });
+</script>