Improve parsing of query string

tests/standalone/io/url_encoding_test.dart

Index: tests/standalone/io/url_encoding_test.dart
diff --git a/tests/standalone/io/url_encoding_test.dart b/tests/standalone/io/url_encoding_test.dart
index c99346ae5b813f38343280ad00cebef3ea8f7edb..74b735004110d1b72276e9b30e08f1607c1d92d4 100644
--- a/tests/standalone/io/url_encoding_test.dart
+++ b/tests/standalone/io/url_encoding_test.dart
@@ -23,19 +23,68 @@ void testParseEncodedString() {
 }
 
 void testParseQueryString() {
+  test(String queryString, Map<String, String> expected) {
+    Map<String, String> map = _HttpUtils.splitQueryString(queryString);
+    for (String key in map.keys) {
+      Expect.equals(expected[key], map[key]);
+    }
+    Expect.setEquals(expected.keys.toSet(), map.keys.toSet());
+  }
+
   // The query string includes escaped "?"s, "&"s, "%"s and "="s.
   // These should not affect the splitting of the string.
-  String queryString =
-      '%3F=%3D&foo=bar&%26=%25&sqrt2=%E2%88%9A2&name=Franti%C5%A1ek';
-  Map<String, String> map = _HttpUtils.splitQueryString(queryString);
-  for (String key in map.keys) {
-    Expect.equals(map[key], { '&'     : '%',
-                              'foo'   : 'bar',
-                              '?'     : '=',
-                              'sqrt2' : '\u221A2',
-                              'name'  : 'Franti\u0161ek'}[key]);
-  }
-  Expect.setEquals(map.keys.toSet(), ['&', '?', 'foo', 'sqrt2', 'name']);
+  test('%3F=%3D&foo=bar&%26=%25&sqrt2=%E2%88%9A2&name=Franti%C5%A1ek',
+       { '&'     : '%',
+         'foo'   : 'bar',
+         '?'     : '=',
+         'sqrt2' : '\u221A2',
+         'name'  : 'Franti\u0161ek'});
+
+  // Same query string with ; as separator.
+  test('%3F=%3D;foo=bar;%26=%25;sqrt2=%E2%88%9A2;name=Franti%C5%A1ek',
+       { '&'     : '%',
+         'foo'   : 'bar',
+         '?'     : '=',
+         'sqrt2' : '\u221A2',
+         'name'  : 'Franti\u0161ek'});
+
+  // Same query string with alternating ; and & separators.
+  test('%3F=%3D&foo=bar;%26=%25&sqrt2=%E2%88%9A2;name=Franti%C5%A1ek',
+       { '&'     : '%',
+         'foo'   : 'bar',
+         '?'     : '=',
+         'sqrt2' : '\u221A2',
+         'name'  : 'Franti\u0161ek'});
+  test('%3F=%3D;foo=bar&%26=%25;sqrt2=%E2%88%9A2&name=Franti%C5%A1ek',
+       { '&'     : '%',
+         'foo'   : 'bar',
+         '?'     : '=',
+         'sqrt2' : '\u221A2',
+         'name'  : 'Franti\u0161ek'});
+
+  // Corner case tests.
+  test('', { });
+  test('&', { });
+  test(';', { });
+  test('&;', { });
+  test(';&', { });
+  test('&&&&', { });
+  test(';;;;', { });
+  test('a', { 'a' : '' });
+  test('&a&', { 'a' : '' });
+  test(';a;', { 'a' : '' });
+  test('a=', { 'a' : '' });
+  test('a=&', { 'a' : '' });
+  test('a=;', { 'a' : '' });
+  test('a=&b', { 'a' : '', 'b' : '' });
+  test('a=;b', { 'a' : '', 'b' : '' });
+  test('a=&b', { 'a' : '', 'b' : '' });
+  test('a=&b=', { 'a' : '', 'b' : '' });
+
+  // These are not really a legal query string.
+  test('=', { });
+  test('=x', { });
+  test('a==&b===', { 'a' : '=', 'b' : '==' });
 }
 
 void main() {