Fix bugs in Uri: Allow empty port, handle path starting with "//" in toString.

tests/corelib/uri_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library uriTest;
 
 import "package:expect/expect.dart";
 import 'dart:convert';
 
 testUri(String uri, bool isAbsolute) {
@@ skipping 129 matching lines @@
 
 void testValidCharacters() {
   // test that all valid characters are accepted.
 
   for (var scheme in ["", "$SCHEMECHAR$SCHEMECHAR:"]) {
     for (var userinfo in ["", "@", "$USERINFOCHAR$USERINFOCHAR@",
                           "$USERINFOCHAR:$DIGIT@"]) {
       for (var host in ["", "$REGNAMECHAR$REGNAMECHAR",
                         "255.255.255.256",  // valid reg-name.
                         "[ffff::ffff:ffff]", "[ffff::255.255.255.255]"]) {
-        for (var port in ["", ":$DIGIT$DIGIT"]) {
+        for (var port in ["", ":", ":$DIGIT$DIGIT"]) {
           var auth = "$userinfo$host$port";
           if (auth.isNotEmpty) auth = "//$auth";
           var paths = ["", "/", "/$PCHAR", "/$PCHAR/"];  // Absolute or empty.
           if (auth.isNotEmpty) {
             // Initial segment may be empty.
             paths..add("//$PCHAR");
           } else {
             // Path may begin with non-slash.
             if (scheme.isEmpty) {
               // Initial segment must not contain colon.
@@ skipping 90 matching lines @@
   }
 
   // At most one @ in userinfo.
   checkInvalid("s://x@x@x.x/");
   // No colon in host except before a port.
   checkInvalid("s://x@x:x/");
   // At most one port.
   checkInvalid("s://x@x:9:9/");
   // At most one #.
   checkInvalid("s://x/x#foo#bar");
-  // Colon in host implies port and port may not be empty.
-  checkInvalid("s://:/");
   // @ not allowed in scheme.
   checkInvalid("s@://x:9/x?x#x");
   // ] not allowed alone in host.
   checkInvalid("s://xx]/");
   // ] not allowed anywhere except in host.
   checkInvalid("s://xx/]");
   checkInvalid("s://xx/?]");
   checkInvalid("s://xx/#]");
   checkInvalid("s:/]");
   checkInvalid("s:/?]");
@@ skipping 60 matching lines @@
   Expect.equals("xxxxxxxxa", uri.host);
 
   uri = Uri.parse("x://%61xxxxxxxx/");
   Expect.equals("axxxxxxxx", uri.host);
 
   uri = Uri.parse("x://X/");
   Expect.equals("x", uri.host);
 
   uri = Uri.parse("x://%61/");
   Expect.equals("a", uri.host);
+
+  uri = new Uri(scheme: "x", path: "//y");
+  Expect.equals("//y", uri.path);
+  Expect.equals("x:////y", uri.toString());
+
+  uri = new Uri(scheme: "file", path: "//y");
+  Expect.equals("//y", uri.path);
+  Expect.equals("file:////y", uri.toString());
+
+  // File scheme noralizes to always showing authority, even if empty.
+  uri = new Uri(scheme: "file", path: "/y");
+  Expect.equals("file:///y", uri.toString());
+  uri = new Uri(scheme: "file", path: "y");
+  Expect.equals("file:///y", uri.toString());
 }
 
 main() {
   testUri("http:", true);
   testUri("file://", true);
   testUri("file", false);
   testUri("http://user@example.com:8080/fisk?query=89&hest=silas", true);
   testUri("http://user@example.com:8080/fisk?query=89&hest=silas#fragment",
           false);
   Expect.stringEquals("http://user@example.com/a/b/c?query#fragment",
@@ skipping 142 matching lines @@
   testEncodeDecodeComponent(s, "%F0%90%80%80");
   testEncodeDecodeQueryComponent("A + B", "A+%2B+B", "A+%2B+B", "A+%2B+B");
   testEncodeDecodeQueryComponent(
       "æ ø å", "%C3%A6+%C3%B8+%C3%A5", "%E6+%F8+%E5", null);
   testEncodeDecodeComponent(nonAscii, nonAsciiEncoding);
 
   // Invalid URI - : and @ is swapped, port ("host") should be numeric.
   Expect.throws(
       () => Uri.parse("file://user@password:host/path"),
       (e) => e is FormatException);
+
+  testValidCharacters();
+  testInvalidUrls();
+  testNormalization();
 }
 
 String dump(Uri uri) {
   return "URI: $uri\n"
       "  Scheme:    ${uri.scheme} #${uri.scheme.length}\n"
       "  User-info: ${uri.userInfo} #${uri.userInfo.length}\n"
       "  Host:      ${uri.host} #${uri.host.length}\n"
       "  Port:      ${uri.port}\n"
       "  Path:      ${uri.path} #${uri.path.length}\n"
       "  Query:     ${uri.query} #${uri.query.length}\n"
       "  Fragment:  ${uri.fragment} #${uri.fragment.length}\n";
 }